题目内容
已知:矩形
的两条对角线相交于点
,
边所在直线的方程为:
,点
在
边所在直线上。
(1)求矩形
外接圆
的方程。
(2)
是
的内接三角形,其重心
的坐标是
,求直线
的方程 .
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353385404.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353401473.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353432234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353448450.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353494314.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353510236.gif)
(1)求矩形
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353385404.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353541202.gif)
(2)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353557400.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353588227.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353604213.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353635271.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353650241.gif)
(1)
的方程为
(2)直线
的方程为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353838481.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353588227.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353791517.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353822234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353838481.gif)
(1)设
点坐标为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353962387.gif)
且
又
在
上
即
点的坐标为
又
点是矩形
两条对角线的交点
点
即为矩形
外接圆的圆心,其半径![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354352552.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354368128.gif)
的方程为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353791517.gif)
(2)连
延长交
于点
,则
点是
中点,连![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354586357.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354602133.gif)
是
的重心,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354758630.gif)
是圆心,
是
中点
, 且 ![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354992417.gif)
即直线
的方程为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353838481.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353853202.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353962387.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353978456.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353994335.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354025410.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354072413.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354087241.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354103762.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354118527.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353853202.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354196302.gif)
又
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354212246.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354228411.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354290242.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354306288.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354228411.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354352552.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354368128.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353588227.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353791517.gif)
(2)连
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354462238.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353822234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354524467.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354555206.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353822234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354586357.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354602133.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354633205.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354711390.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354727494.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354758630.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354836642.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354212246.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354555206.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353822234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354945450.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120354992417.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120355008455.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120355039672.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353822234.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823120353838481.gif)
![](http://thumb.zyjl.cn/images/loading.gif)
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