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【327705】2022年湖南省岳阳市中考数学真题

时间:2025-01-20 20:02:42 作者: 字数:17278字

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2022年湖南省岳阳市中考数学真题

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评卷人

得分




一、选择题

1.8的相反数是(       
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
C
8
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

2.某个立体图形的侧面展开图如图所示,它的底面是正三角形,那么这个立体图形是(       
 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
A
.圆柱
B
.圆锥
C
.三棱柱
D
.四棱柱

3.下列运算结果正确的是(       
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

4.某村通过直播带货对产出的稻虾米进行线上销售,连续7天的销量(单位:袋)分别为:105103105110108105108,这组数据的众数和中位数分别是(       
A
105108
B
105105
C
108105
D
108108

5.如图,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的度数是(       
 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

6.下列命题是真命题的是(       
A
.对顶角相等
B
.平行四边形的对角线互相垂直
C
.三角形的内心是它的三条边的垂直平分线的交点
D
.三角分别相等的两个三角形是全等三角形

7.我国古代数学著作《孙子算经》中有这样一道题,原文如下:今有百鹿入城,家取一鹿,不尽,又三家共一鹿,适尽,问:城中家几何?大意为:今有100头鹿进城,每家取一头鹿,没有取完,剩下的鹿每3家共取一头,恰好取完,问:城中有多少户人家?在这个问题中,城中人家的户数为(       
A
25
B
75
C
81
D
90

8.已知二次函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为常数, <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是该函数图象上一点,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围是(       
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

评卷人

得分




二、填空题

9.使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有意义的 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围是_______

10.2022514日,编号为B-001J <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 大飞机首飞成功.数据显示, <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 大飞机的单价约为65300000元,数据653000000用科学记数法表示为______

11.如图,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

12.分式方程 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ______

13.已知关于 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有两个不相等的实数根,则实数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围是______

14.聚焦“双减”政策落地,凸显寒假作业特色.某学校评选出的寒假优质特色作业共分为四类:A(节日文化篇), <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (安全防疫篇), <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (劳动实践篇), <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (冬奥运动篇)下面是根据统计结果绘制的两幅不完整的统计图,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业有______份.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

15.喜迎二十大,“龙舟故里”赛龙舟.丹丹在汩罗江国际龙舟竞渡中心广场点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 处观看200米直道竞速赛.如图所示,赛道 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为东西方向,赛道起点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 位于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的北偏西 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 方向上,终点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 位于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的北偏东 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 方向上, <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 到赛道 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离约为______米(结果保留整数,参考数据: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

16.如图,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为直径, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为弦,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的切线与 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的延长线交于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上一点(不与点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 重合),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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
1)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的长为______(结果保留 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> );
2)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

18.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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求代数式 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的值.

19.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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 分别在 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> .请从以下三个条件: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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中,选择一个合适的作为已知条件,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为菱形.
 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(1)
你添加的条件是______(填序号);
(2)
添加了条件后,请证明 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为菱形.

20.守护好一江碧水,打造长江最美岸线.江豚,麋鹿,天鹅已成为岳阳“吉祥三宝”的新名片.某校生物兴趣小组设计了3张环保宣传卡片,正面图案如图所示,它们除此之外完全相同.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(1)
将这3张卡片背面朝上,洗匀,从中随机抽取一张,则抽取的卡片正面图案恰好是“麋鹿”的概率为______
(2)
将这3张卡片背面朝上,洗匀,从中随机抽取一张,不放回,再从剩余的两张卡片中随机抽取一张,请用列表或画树状图的方法,求抽取的卡片正面图案恰好是“江豚”和“天鹅”的概率.

21.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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与正比例函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的图象交于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的对称点,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(1)
求该反比例函数的解析式;
(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的面积;
(3)
请结合函数图象,直接写出不等式 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解集.

22.为迎接湖南省第十四届运动会在岳阳举行,某班组织学生参加全民健身线上跳绳活动,需购买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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两种跳绳若干.若购买3A种跳绳和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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳共需140元;若购买5A种跳绳和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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳共需300元.
(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两种跳绳的单价各是多少元?
(2)
若该班准备购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两种跳绳共46根,总费用不超过1780元,那么至多可以购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳多少根?

23.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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的顶点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 重合, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(1)
特例发现:如图1,当点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 分别在 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上时,可以得出结论: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与直线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的位置关系是______
(2)
探究证明:如图2,将图1中的 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 绕点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 顺时针旋转,使点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 恰好落在线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 上,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,(1)中的结论是否仍然成立?若成立,请证明;若不成立,请说明理由;
(3)
拓展运用:如图3,将图1中的 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 绕点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,它们的延长线交于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的值.

24.如图1,在平面直角坐标系 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 经过点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(1)
求抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式;
(2)
如图2,作抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,使它与抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于原点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 成中心对称,请直接写出抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式;
(3)
如图3,将(2)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 向上平移2个单位,得到抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 两点(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 在点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的左侧).
求点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标;
若点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 分别为抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和抛物线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 之间的动点(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 不重合),试求四边形 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积的最大值.

参考答案

1.D

【解析】
根据只有符号不同的两个数叫做互为相反数解答.
解:8的相反数是-8
故选:D

2.C

【解析】
根据常见立体图形的底面和侧面即可得出答案.
解:A选项,圆柱的底面是圆,故该选项不符合题意;
B
选项,圆锥的底面是圆,故该选项不符合题意;
C
选项,三棱柱的底面是三角形,侧面是三个长方形,故该选项符合题意;
D
选项,四棱柱的底面是四边形,故该选项不符合题意;
故选:C

3.A

【解析】
根据合并同类项判断A选项;根据同底数幂的除法判断B选项;根据同底数幂的乘法判断C选项;根据幂的乘方判断D选项.
解:A选项,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故该选项符合题意;
B
选项,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故该选项不符合题意;
C
选项,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故该选项不符合题意;
D
选项,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,故该选项不符合题意;
故选:A

4.B

【解析】
根据众数和中位数的定义求解即可.
解:将这组数据重新排列为103105105105108108110
这组数据出现次数最多的是105
所以众数为105
最中间的数据是105
所以中位数是105
故选:B

5.C

【解析】
根据直角三角形的性质求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,再根据平行线的性质解答即可.
解: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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:C

6.A

【解析】
根据对顶角性质判断A,根据平行四边形的性质判断B,根据三角形的内心定义判断C,根据全等三角形的判定定理判断D
A.
对顶角相等是一个正确的命题,是真命题,故A符合题意;
B.
菱形的对角线互相垂直,非菱形的平行四边形的对角线不垂直,所以平行四边形的对角线互相垂直是一个假命题,故B不符合题意;
C.
三角形的内心是三角形内角平分线的交点,不一定是三边的垂直平分线的交点,则三角形的内心是它的三条边的垂直平分线的交点是一个假命题,故C不符合题意;
D.
三角分别相等的两个三角形不一定全等,故D不符合题意;
故选:A

7.B

【解析】
设城中有 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 户人家,利用鹿的数量 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 城中人均户数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 城中人均户数,即可得出关于 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的一元一次方程,解之即可得出结论.
解:设城中有 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 户人家,
依题意得: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
城中有75户人家.
故选:B

8.A

【解析】
先求出抛物线的对称轴及抛物线与 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的交点坐标,再分两种情况: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,根据二次函数的性质求得 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的不同取值范围便可.
解:∵二次函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
对称轴为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,抛物线与 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的交点为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是该函数图象上一点,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
∴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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,对称轴 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
此时,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,对称轴 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 增大而减小,
则当 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 恒成立;
综上, <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围是: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故选:A

9. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据二次根式的被开方数是非负数列出不等式 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,解不等式即可求得 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

10. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
利用科学记数法的定义解决.科学记数法的表示形式为a×10n的形式,其中1≤|a|10n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.当原数绝对值≥10时,n是正整数;当原数的绝对值<1时,n是负整数.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

11.3

【解析】
根据等腰三角形的性质可知 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的中点,即可求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的长.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为:3

12.2

【解析】
去分母,移项、合并同类项,再对所求的根进行检验即可求解.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
经检验 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是方程的解.
故答案为:2

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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
根据判别式的意义得到 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,然后解不等式求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值即可.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
所以实数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的取值范围是 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

14.20

【解析】
由条形统计图可得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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业分别有25份,30份,25份,由扇形统计图可得 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业份数占总份数的 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可得总份数为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 份,减去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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业的份数即可求解.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业有30份,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业份数占总份数的 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
总份数为: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (份),
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业分别有25份,25份,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 类作业的份数为: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> (份).
故答案为:20

15.87

【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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,垂足为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,然后分别在 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 中,利用锐角三角函数的定义求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的长,再根据 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 米,列出关于 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的方程,进行计算即可解答.
解: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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,垂足为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 到赛道 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的距离约为87米,
故答案为:87
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)根据圆周角定理求出∠AOD=70°,再利用弧长公式求解;
2)解直角三角形求出BCADBD,再利用相似三角形的性质求出DEBE,可得结论.
解:(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的长 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是切线, <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是直径,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是直径,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

17.1

【解析】
根据特殊角的三角函数值,零指数幂,实数的运算,有理数的乘方,绝对值等计算法则求解即可.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

18.-2

【解析】
先化简所求的式子,再结合已知求解即可.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

19.(1)①
(2)
见解析

【解析】
1)添加合适的条件即可;
2)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,再由菱形的判定即可得出结论.
(1)
解:添加的条件是 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
故答案为:①.
(2)
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 为菱形.

20.(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)直接利用概率公式求解即可;
2)将江豚,麋鹿,天鹅三张卡片分别记作①、②、③,列表得出所有等可能结果,从中找到符合条件的结果数,再根据概率公式求解即可.
(1)
将这3张卡片背面朝上,洗匀,从中随机抽取一张,
则抽取的卡片正面图案恰好是“麋鹿”的概率为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
将江豚,麋鹿,天鹅三张卡片分别记作①、②、③,
列表如下:



 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>



由表知,共有6种等可能结果,其中抽取的卡片正面图案恰好是“江豚”和“天鹅”的有2种结果,
所以抽取的卡片正面图案恰好是“江豚”和“天鹅”的概率为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)4
(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)把点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的值,求得反比例函数的解析式;
2)根据对称性求得 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的坐标然后利用三角形面积公式可求解.
3)根据图象得出不等式 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解集即可.
(1)
解:把点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
反比例函数的解析式为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(2)
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 与正比例函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的图象交于点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 是点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴的对称点,
 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
根据图象得:不等式 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解集为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

22.(1)A种跳绳的单价为30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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳的单价为50
(2)
至多可以购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳20

【解析】
1)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳的单价为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳的单价为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元.由题意:若购买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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳和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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳共需 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元;若购买5A种跳绳和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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳共需300元.列出二元一次方程组,解方程组即可;
2)设购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 根,则购买A种跳绳 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 根,由题意:总费用不超过1780元,列出一元一次不等式,解不等式即可.
(1)
解:设A种跳绳的单价为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳的单价为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 元.
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
答:A种跳绳的单价为30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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳的单价为50元.
(2)
设购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 根,则购买A种跳绳 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 根,
由题意得: <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
答:至多可以购买 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 种跳绳20根.

23.(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>  ,垂直
(2)
成立,理由见解析
(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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

【解析】
1)解直角三角形求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可得结论;
2)结论不变,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,推出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可得结论;
3)如图3中,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可得结论.
(1)
解: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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,垂直;
(2)
结论成立.
理由:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
如图3中,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 时,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>

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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ;②12

【解析】
1)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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求解;
2)利用对称性求出函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 顶点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于原点的对称点为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,即可求函数 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式;
3)①通过联立方程组 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点和 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 点坐标即可;
求出直线 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的解析式,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴交 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,可求 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,分别求出 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的最大值4 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 的最大值2,即可求解.
(1)
解: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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 和点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
抛物线的顶点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
顶点 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 关于原点的对称点为 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
(3)
由题意可得,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
联立方程组 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/982/" title="湖南省" class="c1" target="_blank">湖南省</a> <a href="/tags/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a>
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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 轴交 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> ,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有最大值 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 有最大值 <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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 最大时,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/1042/" title="岳阳" class="c1" target="_blank">岳阳</a> <a href="/tags/1121/" title="湖南" class="c1" target="_blank">湖南</a> 面积的最大值为12