题目内容
已知抛物线C:
,
为抛物线上一点,
为
关于
轴对称的点,
为坐标原点.(1)若
,求
点的坐标;
(2)若过满足(1)中的点
作直线
交抛物线
于
两点, 且斜率分别为
,且
,求证:直线
过定点,并求出该定点坐标.
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016834525.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016850831.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016881333.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016912289.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016944266.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016959292.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016990604.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016912289.png)
(2)若过满足(1)中的点
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235016912289.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017068510.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017084313.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017100423.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017131456.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017146521.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017162396.png)
(1)![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017193510.png)
(2)直线
过定点![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017349490.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017193510.png)
(2)直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017162396.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017349490.png)
本试题主要是考查了直线与抛物线的位置关系的运用。
(1)由题意得,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232350173651001.png)
即![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017193510.png)
(2)设直线
的方程为
,![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017474849.png)
直线与抛物线联立得
且![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017521826.png)
由
,得到定点的坐标。
(1)由题意得,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232350173651001.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017396766.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017193510.png)
(2)设直线
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017162396.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017458607.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017474849.png)
直线与抛物线联立得
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017505755.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017521826.png)
由
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823235017536520.png)
![](http://thumb.zyjl.cn/images/loading.gif)
练习册系列答案
相关题目