题目内容
设O为坐标原点,
是双曲线
的焦点,若在双曲线上存在点P,使得
,则双曲线的渐近线方程为( )
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217359458.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042173751110.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042173911044.png)
A.![]() | B.![]() | C.![]() | D.![]() |
D
不妨设
,则![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042175001270.png)
因为
,所以
,
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042175471582.png)
所以![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217562959.png)
因为
在双曲线上,所以![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217609746.png)
则![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176252103.png)
所以
,故![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176711252.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176871301.png)
因为
,所以![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042177341094.png)
故
,即![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217781646.png)
故
,解得![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217812518.png)
所以双曲线的渐近线方程为
,即
,故选D
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217469709.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042175001270.png)
因为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217515697.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042175311607.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042175471582.png)
所以
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217562959.png)
因为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217578289.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217609746.png)
则
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176252103.png)
所以
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217640848.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176711252.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042176871301.png)
因为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217718603.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042177341094.png)
故
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/201408232042177651183.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217781646.png)
故
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217796637.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217812518.png)
所以双曲线的渐近线方程为
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217827753.png)
![](http://thumb.zyjl.cn/pic2/upload/papers/20140823/20140823204217859609.png)
![](http://thumb.zyjl.cn/images/loading.gif)
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A.![]() | B.![]() | C.![]() | D.![]() |