题目内容
已知中心在原点、焦点在x轴的椭圆的离心率为
,且过点(
,
).
(Ⅰ)求椭圆E的方程;
(Ⅱ)若A,B是椭圆E的左、右顶点,直线
:
(
)与椭圆E交于
、
两点,证明直线
与直线
的交点在垂直于
轴的定直线上,并求出该直线方程.![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231321051114520.jpg)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104690225.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104706225.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104737269.gif)
(Ⅰ)求椭圆E的方程;
(Ⅱ)若A,B是椭圆E的左、右顶点,直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104752185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104768467.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104846255.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104862327.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104986211.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105002364.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018251.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018183.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231321051114520.jpg)
(Ⅰ)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105127491.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105002364.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018251.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105252232.gif)
(Ⅰ)依题意,设椭圆
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105267204.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105298729.gif)
由已知
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105361226.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104690225.gif)
∵点(
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104706225.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104737269.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105423243.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105501381.gif)
由①、②及
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105532412.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105564252.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105610251.gif)
∴椭圆
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105267204.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105127491.gif)
(Ⅱ)将直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104752185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104768467.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105127491.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105766863.gif)
设直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132104752185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105267204.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105844486.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105860466.gif)
由根与系数的关系,得
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105891620.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105907697.gif)
消去
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105922214.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105938603.gif)
直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105002364.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105969602.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105985727.gif)
直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018251.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132106094600.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132106110726.gif)
由直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105002364.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018251.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132106156193.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231321061721483.gif)
∴直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105002364.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105018251.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823132105252232.gif)
![](http://thumb.zyjl.cn/images/loading.gif)
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