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【327841】2023年江苏省徐州市中考数学真题

时间:2025-01-20 20:27:06 作者: 字数:20258字
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绝密·启用前

2023年江苏省徐州市中考数学真题

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得分





注意事项:

1.答题前填写好自己的姓名、班级、考号等信息

2.请将答案正确填写在答题卡上



评卷人

得分




一、选择题

1.下列事件中的必然事件是(       
A
.地球绕着太阳转
B
.射击运动员射击一次,命中靶心
C
.天空出现三个太阳
D
.经过有交通信号灯的路口,遇到红灯

2.下列图案是中心对称图形但不是轴对称图形的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
B <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
C <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

3.如图,数轴上点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 分别对应实数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,下列各式的值最小的是(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>           
A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

4.下列运算正确的是(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

5.徐州云龙山共九节,蜿蜒起伏,形似游龙,每节山的海拔如图所示.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
其中,海拔为中位数的是(       
A
.第五节山
B
.第六节山
C
.第八节山
D
.第九节山

6. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的值介于(       
A
2530之间
B
3035之间
C
3540之间
D
4045之间

7.在平面直角坐标系中,将二次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象向右平移2个单位长度,再向下平移1个单位长度,所得拋物线对应的函数表达式为(       
A
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

8.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点.若点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长为(       
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
A1
B
2
C
1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D
12

评卷人

得分




二、填空题

9.若一个三角形的边长均为整数,且两边长分别为35,则第三边的长可以为________(写出一个即可).

10.五一”假期我市共接待游客约4370000人次,将4370000用科学记数法表示为________

11.若代数式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有意义,则x的取值范围是 _____

12.正五边形的一个外角的大小为__________度.

13.关于x的方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有两个相等的实数根,则m的值是______

14.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ________°
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

15.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中,直径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 与弦 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的切线与 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</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/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ________°
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

16.如图,沿一条母线将圆锥侧面剪开并展平,得到一个扇形,若圆锥母线l=6,扇形的圆心角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则该圆锥的底面圆的半径r长为______
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

17.如图,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象上, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .一次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的值为_______
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

18.如图,在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上.将 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 沿 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 折叠,使点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 落在点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 处,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的最小值为_______
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

评卷人

得分




三、解答题

19.计算:
(1)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

20.1)解方程组 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解不等式组 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

21.为了解某地区九年级学生的视力情况,从该地区九年级学生中抽查了部分学生,根据调查结果,绘制了如下两幅不完整的统计图.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
根据以上信息,解决下列问题:
(1)
此次调查的样本容量为
(2)
扇形统计图中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 对应圆心角的度数为 °
(3)
请补全条形统计图;
(4)
若该地区九年级学生共有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 人,请估计其中视力正常的人数.

22.甲,乙、丙三人到淮海战役烈士纪念塔园林游览,若每人分别从纪念塔、纪念馆这两个景点中选择一个参观,且选择每个景点的机会相等,则三人选择相同景点的概率为多少?

23.随着2022年底城东快速路的全线通车,徐州主城区与东区之间的交通得以有效改善,如图某人乘车从徐州东站至戏马台景区,可沿甲路线或乙路线前往.已知甲、乙两条路线的长度均为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,甲路线的平均速度为乙路线的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 倍,甲路线的行驶时间比乙路线少 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,求甲路线的行驶时间.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

24.如图,正方形纸片 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的边长为4,将它剪去4个全等的直角三角形,得到四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的函数表达式;
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 取何值时,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积为10
(3)
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积是否存在最小值?若存在,求出最小值;若不存在,请说明理由.

25.徐州电视塔为我市的标志性建筑之一,如图,为了测量其高度,小明在云龙公园的点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 处,用测角仪测得塔顶 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的仰角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,他在平地上沿正对电视塔的方向后退至点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 处,测得塔顶 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的仰角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .若测角仪距地面的高度 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,求电视塔的高度 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> (精确到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .(参考数据: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>     <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

26.两汉文化看徐州,桐桐在徐州博物馆“天工汉玉”展厅参观时了解到;玉壁,玉环为我国的传统玉器,通常为正中带圆孔的扇圆型器物,据《尔雅·释器》记载:“肉倍好,谓之璧;肉好若一,调之环.”如图1,“肉”指边(阴影部分),“好”指孔,其比例关系见图示,以考古发现看,这两种玉器的“肉”与“好”未必符合该比例关系.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(1)
若图1中两个大圆的直径相等,则璧与环的“肉”的面积之比为
(2)
利用圆规与无刻度的直尺,解决下列问题(保留作图痕迹,不写作法).
2为徐州狮子山楚王墓出土的“雷纹玉环”及其主视图,试判断该件玉器的比例关系是否符合“肉好若一”?
3表示一件圆形玉坯,若将其加工成玉璧,且比例关系符合“肉倍好”,请画出内孔.

27.(阅读理解)如图1,在矩形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,由勾股定理,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,同理 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,故 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(
探究发现)如图2,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为平行四边形,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则上述结论是否依然成立?请加以判断,并说明理由.
(
拓展提升)如图3,已知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的一条中线, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .求证: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(
尝试应用)如图4,在矩形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,点P在边 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的最小值为_______  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

28.如图,在平而直角坐标系中,二次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象与 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴分别交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,顶点为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,将线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 绕点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 按顺时针方向旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 得到线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> .点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 分别在线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 交于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
(1)求点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的坐标;
(2)
随着点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上运动.
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的大小是否发生变化?请说明理由;
线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长度是否存在最大值?若存在,求出最大值;若不存在,请说明理由;
(3)
当线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点在该二次函数的因象的对称轴上时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积为

参考答案

1.A

【解析】
根据必然事件、不可能事件、随机事件的概念,可得答案.
解∶ A、地球绕着太阳转是必然事件,故A正确;
B
、射击运动员射击一次,命中靶心是随机事件,故B错误;
C
、天空出现三个太阳是不可能事件,故C错误;
D
、经过有交通信号灯的路口,遇到红灯是随机事件,故D错误;
故选∶ A

2.A

【解析】
根据轴对称图形:一个图形如果沿一条直线折叠,直线两旁部分能够完全重合的图形;中心对称图形:一个图形绕某个点旋转180度后能与原图完全重合的图形;由此问题可求解.
解:A、是中心对称图形但不是轴对称图形,故符合题意;
B
、是轴对称图形,但不是中心对称图形,故不符合题意;
C
、既是轴对称图形也是中心对称图形,故不符合题意;
D
、既不是轴对称图形也不是中心对称图形,故不符合题意;
故选A

3.C

【解析】
根据数轴可直接进行求解.
解:由数轴可知点C离原点最近,所以在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中最小的是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故选C

4.B

【解析】
根据同底数幂的乘除法、幂的乘方及合并同类项可进行求解.
解:A <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,原计算错误,故不符合题意;
B
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,原计算正确,故符合题意;
C
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,原计算错误,故不符合题意;
D
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,原计算错误,故不符合题意;
故选B

5.C

【解析】
根据折线统计图把数据按从小到大排列,然后根据中位数可进行求解.
解:由折线统计图可按从小到大排列为90.799.2104.1119.2131.8133.5136.6139.6141.6,所以海拔为中位数的是第5个数据,即为第八节山;
故选C

6.D

【解析】
直接利用二次根式的性质得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的取值范围进而得出答案.
解∶∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的值介于4045之间.
故选D

7.B

【解析】
根据二次函数图象的平移“左加右减,上加下减”可进行求解.
解:由二次函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象向右平移2个单位长度,再向下平移1个单位长度,所得拋物线对应的函数表达式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故选B

8.D

【解析】
根据题意易得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后根据题意可进行求解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
D <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
当点E <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点时,如图,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
当点E <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的四等分点时,如图所示:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
综上所述: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 2
故选D

9.4

【解析】
根据三角形三边关系可进行求解.
解:设第三边的长为x,则有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
该三角形的边长均为整数,
第三边的长可以为34567
故答案为4(答案不唯一).

10. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
科学记数法的表示形式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的形式,其中 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> n为整数.确定n的值时,要看把原数变成a时,小数点移动了多少位,n的绝对值与小数点移动的位数相同.当原数绝对值大于或等于10时,n是正整数;当原数的绝对值小于1时,n是负整数.
解:将4370000用科学记数法表示为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

11. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ## <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有意义得出 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,再求出答案即可.
解:∵代数式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有意义,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

12.72

【解析】
根据多边形的外角和是360°,依此即可求解.
解:正五边形的一个外角的度数为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为:72

13. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
根据一元二次方程根与判别式的关系可得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,求解即可.
解:关于x的方程 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 有两个相等的实数根,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

14. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ##55

【解析】
先由邻补角求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,进而由平行线的性质求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,最后利用三角形的内角和定理即可得解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

15.66

【解析】
连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后可得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,进而问题可求解.
解:连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,如图所示:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的直径,且 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的切线,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为:66

16.2

【解析】
结合题意,根据弧长公式,可求得圆锥的底面圆周长.再根据圆的周长的公式即可求得底面圆的半径长.
母线l长为6,扇形的圆心角 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
圆锥的底面圆周长 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
圆锥的底面圆半径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为:2

17.4

【解析】
根据题意可设点P的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,把 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 代入一次函数解析式中求出m的值进而求出点P的坐标,再求出k的值即可.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 轴于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
P的横纵坐标相同,
可设点P的坐标为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在直线 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在反比例函数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的图象上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为:4

18. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
由折叠性质可知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后根据三角不等关系可进行求解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
由折叠的性质可知 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> B三点在同一条直线时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 取最小值,最小值即为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

19.(1)2022
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)根据零次幂、负指数幂及算术平方根可进行求解;
2)根据分式的运算可进行求解.
1)解:原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解:原式 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

20.1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ;(2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)利用代入法解二元一次方程组即可;
2)求出每个不等式的解集,取每个不等式解集的公共部分即可.
解:(1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
把①代入②得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 代入①得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解不等式①得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解不等式②得, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
不等式组的解集是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

21.(1)450
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(3)
见解析
(4)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1)根据 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的人数是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 人,所占的比例是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,据此即可求得此次调查的样本容量;
2)用 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 类学生数除以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,再乘以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 即可得解;
3)利用总人数减去 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 三类的人数即可求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的人数,从而补全直方图;
4)利用总人数 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 乘以对应的百分比即可求得.
1)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
答:此次调查的样本容量为是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
3)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
补全图形如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
4)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> (人)
答:九年级学生共有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 人,请估计其中视力正常的人数共有 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 人.

22. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
根据树状图可进行求解概率.
解:由题意可得如下树状图:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
甲、乙、丙三人分别从纪念塔、纪念馆这两个景点中选择一个参观,则共有8种情况,其中三人选择相同景点参观共有2种,所以三人选择相同景点的概率为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

23.甲路线的行驶时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
设甲路线的行驶时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则乙路线的行驶事件为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,根据“甲路线的平均速度为乙路线的 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 倍”列分式方程求解即可.
解:甲路线的行驶时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则乙路线的行驶事件为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,由题意可得,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
经检验 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是原方程的解,
甲路线的行驶时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
答:甲路线的行驶时间为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

24.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 13时,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积为10
(3)
存在,最小值为8

【解析】
1)先证出四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为正方形,用未知数x表示其任一边长,根据正方形面积公式即可解决问题;
2)代入y值,解一元二次方程即可;
3)把二次函数配方化为顶点式,结合其性质即可求出最小值.
1)解: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 在正方形纸片 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上剪去4个全等的直角三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为正方形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 正方形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 不能为负,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 关于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的函数表达式为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解:令 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
整理,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 13时,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积为10
3)解:存在.
正方形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 时,y有最小值8,即四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的面积最小为8

25. <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
先证四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是矩形,四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是平行四边形,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中,解直角三角形以及由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 构造方程求解即可得解.
解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是平行四边形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 中, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
电视塔的高度 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

26.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)①
符合,图见详解;②图见详解

【解析】
1)根据圆环面积可进行求解;
2)①先确定该圆环的圆心,然后利用圆规确定其比例关系即可;②先确定好圆的圆心,然后根据平行线所截线段成比例可进行作图.
1)解:由图1可知:璧的“肉”的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ;环的“肉”的面积为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
它们的面积之比为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解:①在该圆环任意画两条相交的线,且交点在外圆的圆上,且与外圆的交点分别为ABC,则分别以AB为圆心,大于 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 长为半径画弧,交于两点,连接这两点,同理可画出线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的垂直平分线,线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的垂直平分线的交点即为圆心O,过圆心O画一条直径,以O为圆心,内圆半径为半径画弧,看是否满足“肉好若一”的比例关系即可
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
由作图可知满足比例关系为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的关系;
按照①中作出圆的圆心O,过圆心画一条直径 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,过点A作一条射线,然后以A为圆心,适当长为半径画弧,把射线三等分,交点分别为CDE,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,然后分别过点CD <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的平行线,交 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 于点FG,进而以 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为直径画圆,则问题得解;如图所示:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    

27.探究发现:结论依然成立,理由见解析;拓展提升:证明见解析;尝试应用: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
探究发现:作 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 于点E,作 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的延长线于点F,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,利用勾股定理进行计算即可得到答案;
拓展提升:延长 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 到点C,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,证明四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是平行四边形,由(探究发现)可知, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即可得到结论;
尝试应用:由四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,由勾股定理得到 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,根据二次函数的性质即可得到答案.
探究发现:结论依然成立,理由如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 于点E,作 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的延长线于点F,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 为平行四边形,若 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
拓展提升:延长 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 到点C,使 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的一条中线,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是平行四边形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(探究发现)可知, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
尝试应用:∵四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是矩形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,则 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
抛物线开口向上,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的最小值是 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为: <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

28.(1) <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(2)①
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的大小不变,理由见解析;②线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长度存在最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
(3)
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>

【解析】
1 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,解方程即可求得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的坐标,把 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 化为顶点式即可求得点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的坐标;
2)①在 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上取点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,使得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形即可得出结论;②由 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,得当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 最小时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长最大,即当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长最大,进而解直角三角形即可求解;
3)设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,证四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是菱形,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,进而证明 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,再证 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,结合三角形的面积公式即可求解.
1)解:∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
顶点为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
解得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
2)解:① <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的大小不变,理由如下:
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 上取点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,使得 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
抛物线对称轴为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
将线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 绕点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 按顺时针方向旋转 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 得到线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的大小不变;
,∵ <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 最小时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长最大,即当 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 时, <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长最大,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,即线段 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的长度存在最大值为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
3)解:设 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,连接 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> ,过点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 于点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
四边形 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是菱形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 的中点为点 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a> 是等边三角形,
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>  <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>    
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>
故答案为 <a href="/tags/55/" title="数学" class="c1" target="_blank">数学</a> <a href="/tags/558/" title="江苏" class="c1" target="_blank">江苏</a> <a href="/tags/744/" title="江苏省" class="c1" target="_blank">江苏省</a> <a href="/tags/1049/" title="徐州" class="c1" target="_blank">徐州</a>