解题方法
1 . 图1所示的椭圆规是画椭圆的一种工具,在十字形滑槽上各有一个活动滑标M,N,有一根旋杆将两个滑标连成一体,
,D为旋杆上的一点且在M,N两点之间,且
.当滑标M在滑槽EF内做往复运动,滑标N在滑槽GH内随之运动时,将笔尖放置于D处可画出椭圆,记该椭圆为
.如图2所示,设EF与GH交于点O,以EF所在的直线为x轴,以GH所在的直线为y轴,建立平面直角坐标系.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/3b17f226-9d2d-4f39-9690-3d5c9e5d818a.png?resizew=373)
(1)求椭圆
的方程;
(2)以椭圆
的短轴为直径作圆
,已知直线l与圆
相切,且与椭圆
交于A,B两点,记△OAB的面积为S,若
,求直线l的斜率.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cbdd945cdadb7dca0d281d791374573.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58176dcb4db792f9ee2581e50abb66f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/3b17f226-9d2d-4f39-9690-3d5c9e5d818a.png?resizew=373)
(1)求椭圆
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
(2)以椭圆
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f3ffe7abc59e2f65d827c8eab8d36a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23f3ffe7abc59e2f65d827c8eab8d36a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96cf403e3164aa005336d2869ad8c2a6.png)
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