1 . 在一次数学探究活动中,李老师设计了一份活动单:
学习小组通过操作、观察、讨论后得到:点A的位置不唯一,它在以
为弦的圆弧上(点B、C除外)……小华同学画出了符合要求的一条圆弧(如图1).
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/267f0b4bdc614da6b00d2df012f1bbbc.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/71d89a1332fc42c48cc62c40f764fa24.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/71d89a1332fc42c48cc62c40f764fa24.png?resizew=175)
(1)小华同学提出了下列问题,请你帮助解决.
①该弧所在圆的半径长为 :②
面积的最大值为 ;
(2)经过比对发现,小明同学所画的角的顶点不在小华所画的圆弧上,而在如图1所示的弓形内部,我们记为
,请你利用图1证明
;
(3)请你运用所学知识,结合以上活动经验,解决问题:如图2,已知矩形
的边长为
,
,点P在直线
的左侧,且
.
①线段
长的最小值为 ;
②若
,求线段
的长.
已知线段![]() ![]() (1)这样的点A唯一吗? (2)点A的位置有什么特征?你有什么感悟? |
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/267f0b4bdc614da6b00d2df012f1bbbc.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/71d89a1332fc42c48cc62c40f764fa24.png?resizew=175)
![](https://img.xkw.com/dksih/QBM/2022/10/18/3090504502640640/3099752344616960/STEM/71d89a1332fc42c48cc62c40f764fa24.png?resizew=175)
图1 图2 备用图
(1)小华同学提出了下列问题,请你帮助解决.
①该弧所在圆的半径长为 :②
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)经过比对发现,小明同学所画的角的顶点不在小华所画的圆弧上,而在如图1所示的弓形内部,我们记为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cc0ff2f59c2273aa45f3ff04884677d9.png)
(3)请你运用所学知识,结合以上活动经验,解决问题:如图2,已知矩形
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b83cb6327dcbc8a998e6586bcfa7a3b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63247af194edc9d72cd3ca7365a5d128.png)
①线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b359f096d4698f7acd6aecd5dea70229.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
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