题目内容
已知抛物线
,点
为坐标原点,斜率为1的
直线与抛物线交于
两点
(1)若直线
过点
且
,求
的面积;
(2)若直线
过抛物线的焦点且
,求抛物线的方程.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651581061175.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157919528.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157935209.gif)
直线与抛物线交于
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157966248.gif)
(1)若直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157997323.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158028236.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158044294.gif)
(2)若直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158075394.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651581061175.gif)
(1)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651581381115.gif)
(2)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158153390.gif)
解:(1)依题意得:直线
的方程为
,抛物线方程为
,
,
,设直线
与抛物线交点![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158356603.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651584031115.gif)
(2)依题意得:直线
的方程为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158434436.gif)
,
,设直线
与抛物线交点![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158356603.gif)
,又已知
即![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158574489.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651585901748.gif)
所求抛物线方程为![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158153390.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158200389.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158153390.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158309824.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158325273.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158356603.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158372671.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651584031115.gif)
(2)依题意得:直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158434436.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158450949.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158325273.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165157982185.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158356603.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158528628.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158075394.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158574489.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408231651585901748.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158606128.gif)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823165158153390.gif)
![](http://thumb.zyjl.cn/images/loading.gif)
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