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【327825】2023年湖南省怀化市中考数学真题

时间:2025-01-20 20:23:05 作者: 字数:18480字

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2023年湖南省怀化市中考数学真题

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一、选择题

1.下列四个实数中,最小的数是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
0
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

2.202341221时,正在运行的中国大科学装置“人造太阳”——世界首个全超导托卡马克东方超环(EAST)装置取得重大成果,在第122254次实验中成功实现了403秒稳态长脉冲高约束模式等离子体运行,创造了托卡马克装置高约束模式运行新的世界纪录.数据122254用科学记数法表示为(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

3.下列计算正确的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

4.剪纸又称刻纸,是中国最古老的民间艺术之一,它是以纸为加工对象,以剪刀(或刻刀)为工具进行创作的艺术.民间剪纸往往通过谐音、象征、寓意等手法提炼、概括自然形态,构成美丽的图案.下列剪纸中,既是轴对称图形,又是中心对称图形的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    

5.在平面直角坐标系中,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于x轴对称的点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

6.如图,平移直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 被直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 所截, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的度数为(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

7.某县“三独”比赛独唱项目中,5名同学的得分分别是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 9.6 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .关于这组数据,下列说法正确的是(       
A
.众数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
.中位数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
.平均数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
.方差是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

8.下列说法错误的是(       
A
.成语“水中捞月”表示的事件是不可能事件
B
.一元二次方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有两个相等的实数根
C
.任意多边形的外角和等于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
.三角形三条中线的交点叫作三角形的重心

9.已知压力 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 、压强 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与受力面积 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 之间有如下关系式: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .当F为定值时,下图中大致表示压强P与受力面积S之间函数关系的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    

10.如图,反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的图象与过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 相交于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两点.已知点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴上任意一点.如果 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,那么点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

评卷人

得分




二、填空题

11.要使代数式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有意义,则x的取值范围是__________

12.分解因式: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> _____

13.已知关于x的一元二次方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的一个根为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则m的值为__________,另一个根为__________

14.定义新运算: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为实数.例如: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .如果 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,那么 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> __________

15.如图,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是正方形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的对角线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上的一点, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .则点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 到直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离为__________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    

16.在平面直角坐标系中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为等边三角形,点A的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .把 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 按如图所示的方式放置,并将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 进行变换:第一次变换将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 绕着原点O顺时针旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,同时边长扩大为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 边长的2倍,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ;第二次旋转将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 绕着原点O顺时针旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,同时边长扩大为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,边长的2倍,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,….依次类推,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的边长为__________,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为__________
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    

评卷人

得分




三、解答题

17.计算: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

18.先化简 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,再从 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 012中选择一个适当的数作为a的值代入求值.

19.如图,矩形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中,过对角线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的垂线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,分别交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
(1)证明: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,证明:四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是菱形.

20.为弘扬革命传统精神,清明期间,某校组织学生前往怀化市烈士陵园缅怀革命先烈.大家被革命烈士纪念碑的雄伟壮观震撼,想知道纪念碑的通高 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (碑顶到水平地面的距离),于是师生组成综合实践小组进行测量.他们在地面的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点用测角仪测得碑顶 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的仰角为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点处测得碑顶 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的仰角为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,已知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,测角仪的高度是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在同一直线上),根据以上数据求烈士纪念碑的通高 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .( <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,结果保留一位小数)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>     <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    

21.近年,“青少年视力健康”受到社会的广泛关注.某校综合实践小组为了解该校学生的视力健康状况,从全校学生中随机抽取部分学生进行视力调查.根据调查结果和视力有关标准,绘制了两幅不完整的统计图.请根据图中信息解答下列问题:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
(1)所抽取的学生人数为__________
(2)
补全条形统计图,并求出扇形统计图中“轻度近视”对应的扇形的圆心角的度数;
(3)
该校共有学生 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,请估计该校学生中近视程度为“轻度近视”的人数.

22.如图, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的直径,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 外一点, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 相切于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上的一点.连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
(1)求证: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的切线;
(2)
延长 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的延长线交于点D,求证: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求阴影部分的面积.

23.某中学组织学生研学,原计划租用可坐乘客 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车若干辆,则有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人没有座位;若租用可坐乘客 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车,则可少租 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,且恰好坐满.
(1)
求原计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车多少辆?这次研学去了多少人?
(2)
若该校计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两种客车共 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,要求 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车不超过 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,且每人都有座位,则有哪几种租车方案?
(3)
在(2)的条件下,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车租金为每辆 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车租金每辆 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元,应该怎样租车才最合算?

24.如图一所示,在平面直角坐标系中,抛物线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴交于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两点,与 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
(1)求抛物线的函数表达式及顶点坐标;
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为第三象限内抛物线上一点,作直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积的最大值及此时点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标;
(3)
设直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 交抛物线于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求证:无论 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为何值,平行于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上总存在一点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,使得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直角.

参考答案

1.A

【解析】
先根据实数的大小比较法则比较数的大小,再求出最的数即可.

 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 最小的数是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:A

2.C

【解析】
科学记数法的表示形式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的形式,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> n为整数.确定n的值时,要看把原数变成a时,小数点移动了多少位,n的绝对值与小数点移动的位数相同.
解:数据122254用科学记数法表示为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:C

3.A

【解析】
根据同底数幂的乘法、同底数幂的除法、积的乘方和幂的乘方、合并同类项分别计算后,即可得到答案.
解:A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故选项正确,符合题意;
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故选项错误,不符合题意;
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故选项错误,不符合题意;
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故选项错误,不符合题意.
故选:A

4.C

【解析】
根据轴对称图形和中心对称图形的定义:如果一个平面图形沿一条直线折叠,直线两旁的部分能够互相重合,这个图形就叫做轴对称图形;中心对称图形的定义:把一个图形绕着某一个点旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,如果旋转后的图形能够与原来的图形重合,那么这个图形叫做中心对称图形,这个点就是它的对称中心,进行逐一判断即可.
解:A、不是轴对称图形,是中心对称图形,故A选项不合题意;
B
、是轴对称图形,不是中心对称图形,故B选项不合题意.
C
、既是轴对称图形又是中心对称图形,故C选项符合题意;
D
、是轴对称图形,不是中心对称图形,故D选项不合题意.
故选:C

5.D

【解析】
根据关于x轴对称的两个点,横坐标相等,纵坐标互为相反数,即可求解.
解:点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于x轴对称的点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:D

6.B

【解析】
根据平移可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据平行线的性质以及对顶角相等,即可求解.
解:如图所示,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
平移直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,
又∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:B

7.A

【解析】
先把5个数据按从小到大的顺序排列,而后用中位数,众数,平均数和方差的定义及计算方法逐一判断.
解:5个数按从小到大的顺序排列 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 9.6 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 出现次数最多,众数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故正确,符合题意;
B
、中位数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故不正确,不符合题意;
C
、平均数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故不正确,不符合题意;
D
、方差是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故不正确,不符合题意.
故选:A

8.B

【解析】
根据不可能事件、根的判别式、多边形的外角和以及三角形的重心的定义分别进行判断即可.
解:A、成语“水中捞月”表示的事件是不可能事件,故此选项不符合题意;
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则一元二次方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 没有实数根,故此选项符合题意;
C
、任意多边形的外角和等于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故此选项不符合题意;
D
、三角形三条中线的交点叫作三角形的重心,故此选项不符合题意;
故选:B

9.D

【解析】
根据反比例函数的定义,即可得到答案.
解:根据题意得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
当物体的压力F为定值时,该物体的压强P与受力面积S的函数关系式是: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
则函数图象是双曲线,同时自变量是正数.
故选:D

10.D

【解析】
反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的图象过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,进而求得直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点的坐标,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,解方程即可求解.
解:∵反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的图象过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
设直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,
直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
联立 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:D

11. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据二次根式有意义的条件得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解.
解:∵代数式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有意义,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

12. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
解:先提取公因式2后继续应用完全平方公式分解即可:
原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

13.      <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>       <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 代入原方程,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据一元二次方程根与系数的关系,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解.
解:∵关于x的一元二次方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的一个根为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
设原方程的另一个根为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

14. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据新定义列出一元一次方程,解方程即可求解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

15. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,证明四边形四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是正方形,即可求解.
解:如图所示,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是正方形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的对角线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上的一点, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是等腰直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是正方形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
即点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 到直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

16.      <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>       <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据旋转角度为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可知每旋转6次后点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 又回到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的正半轴上,故点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第四象限,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为等边三角形,点A的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
每次旋转角度为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
∴6
次旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第一次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第四象限, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第二次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第三象限, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第三次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴负半轴, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第四次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第二象限, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第五次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第一象限, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
第六次旋转后, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴正半轴, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
……
如此循环,每旋转6次,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的对应点又回到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴正半轴,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在第四象限,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
如图,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

17. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
先计算负整数指数幂、算术平方根、零指数幂、减法运算,再进行加减混合运算即可.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

18. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,原式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ;当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,原式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
本题先对要求的式子进行化简,再选取一个适当的数代入即可求出结果.
解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
a <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 12时分式没有意义,
所以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 0
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

19.(1)见解析
(2)
见解析

【解析】
1)根据矩形的性质得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点,可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
2)根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,进而可得四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是平行四边形,根据对角线互相垂直的四边形是菱形,即可得证.
1)证明:如图所示,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是矩形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
2)∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
又∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是平行四边形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是菱形.

20.烈士纪念碑的通高 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 约为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据题意,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,根据三角形的外角的性质得出, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,等角对等边得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,进而解 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,最后根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解.
解:依题意,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

21.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
统计图见解析, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)用“视力正常”的人数除以其人数占比即可求出抽取的学生人数;
2)先求出“中度近视”的人数,进而求出“轻度近视”的人数,由此补全统计图即可;再用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 乘以“轻度近视”的人数占比即可求出对应的圆心角度数;
3)用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 乘以样本中“轻度近视”的人数占比即可得到答案.
1)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,
所抽取的学生人数为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
2)解:中度近视的人数为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,“轻度近视”对应的扇形的圆心角的度数为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
高度近视的人数为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,
补全统计图如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
3)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人,
估计该校学生中近视程度为“轻度近视”的人数为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人.

22.(1)见解析
(2)
见解析
(3)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可得证;
2)根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可得证;
3)根据圆周角定理得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,进而勾股定理求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解.
1)证明:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的切线,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
如图所示,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上的一点.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的切线;
2)∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的切线;
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
3)解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

23.(1)原计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,这次研学去了 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
共有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种租车方案,方案一:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆;方案二:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆;方案三:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,
(3)
租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆才最合算

【解析】
1)设原计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,根据题意列出一元一次方程,解方程即可求解;
2)设租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,根据题意列出一元一次不等式组,解不等式组即可求解;
3)分别求得三种方案的费用,进而即可求解.
1)解:设原计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,根据题意得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
所以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (人)
答:原计划租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,这次研学去了 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 人;
2)解:设租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,根据题意,得
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为正整数,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
共有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种租车方案,
方案一:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,
方案二:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,
方案三:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,
3)∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车租金为每辆 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车租金每辆 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车越少,费用越低,
方案一:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,费用为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元,
方案二:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,费用为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元,
方案三:租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,费用为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元,
租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆,则租用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种客车 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 辆才最合算.

24.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积的最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,此时点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
见解析

【解析】
1)待定系数法求解析式即可求解;
2)如图所示,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得出直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 取得最大值时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积取得最大值,进而根据二次函数的性质即可求解;
3)设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,联立 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,消去 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,整理得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,依题意, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点总在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直径,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 相切,即可得证.
1)解:将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 代入 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,得
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
抛物线解析式为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
2)解:如图所示,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,令 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
设直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,将点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 代入得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 取得最大值时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积取得最大值
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积的最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
此时 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
3)解:设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
联立 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,消去 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,整理得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点总在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直径,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 相切,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直角.
无论 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为何值,平行于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上总存在一点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,使得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1037/" title="怀化" class="c1" target="_blank">怀化</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直角.