lxdh
幼苗
共回答了25个问题采纳率:100% 举报
已知双曲线
![](https://img.yulucn.com/upload/4/fe/4fe2ba7a7bb8264c132e5afb1e71bfe4_thumb.jpg)
="1"
![](https://img.yulucn.com/upload/5/a4/5a43cb13fccaf05a67b423432310e7d9_thumb.jpg)
的两个焦点为
![](https://img.yulucn.com/upload/e/a9/ea910515474788dab2e8814d5791ad1f_thumb.jpg)
、
![](https://img.yulucn.com/upload/4/a2/4a2be68af218a7664588d9b119f77baf_thumb.jpg)
,P是双曲线上的一点,
且满足
![](https://img.yulucn.com/upload/6/1a/61a2847e6aab18b5fb7497a13b24e261_thumb.jpg)
,
(1)求
![](https://img.yulucn.com/upload/a/93/a9308bb91cffa3476ec1dcf8873c3a74_thumb.jpg)
的值;
(2)抛物线
![](https://img.yulucn.com/upload/9/12/9123e63c0b3eaa4dca4b1b97607448e7_thumb.jpg)
的焦点F与该双曲线的右顶点重合,斜率为1的直线经过点F与该抛物线交于A、B两点,求弦长|AB|.
(1)
![](https://img.yulucn.com/upload/a/f6/af6bb76f9d6196bc28a6814bd32e1b78_thumb.jpg)
(2)16
(1)根据题意
![](https://img.yulucn.com/upload/c/20/c20dce2a370b671e318e58d05d3a59a3_thumb.jpg)
,
又,
![](https://img.yulucn.com/upload/3/37/337e43751848b1d8a32dbae2818f2e0e_thumb.jpg)
,
![](https://img.yulucn.com/upload/b/4a/b4ad84faaddd663aa4f0172338ae8093_thumb.jpg)
,又|P F
![](https://img.yulucn.com/upload/a/35/a35d7a7ee36ba8d3d63dfc6b6ed0ab2c_thumb.jpg)
|•|PF
![](https://img.yulucn.com/upload/4/6c/46c10956f69c7df7367c21560df0e8af_thumb.jpg)
|="|" F
![](https://img.yulucn.com/upload/a/35/a35d7a7ee36ba8d3d63dfc6b6ed0ab2c_thumb.jpg)
F
![](https://img.yulucn.com/upload/4/6c/46c10956f69c7df7367c21560df0e8af_thumb.jpg)
|
![](https://img.yulucn.com/upload/9/5b/95b37a357eb6a49d0b0e501cfcf46f4f_thumb.jpg)
=
![](https://img.yulucn.com/upload/5/c1/5c1ce451f0cc9a54f1e670774afbf32b_thumb.jpg)
, |P F
![](https://img.yulucn.com/upload/4/6c/46c10956f69c7df7367c21560df0e8af_thumb.jpg)
|<4, 得
![](https://img.yulucn.com/upload/d/8e/d8ee352697ad0a4330f8b0ef5e3e6e26_thumb.jpg)
在区间(0,4)上有解, 所以
因此
![](https://img.yulucn.com/upload/5/9d/59d182608883db3319abeb8019d30663_thumb.jpg)
,又
![](https://img.yulucn.com/upload/4/39/439f244e350ca3a8fbc760de839b9c96_thumb.jpg)
,所以
(2)双曲线方程为
![](https://img.yulucn.com/upload/6/53/65370095c7f0871d4fefdcf1b31e03fe_thumb.jpg)
=1,右顶点坐标为(2,0),即
所以抛物线方程为
![](https://img.yulucn.com/upload/5/c1/5c186057579c2dadc90846b35b97dfdb_thumb.jpg)
直线方程为
由(1)(2)两式联立,解得
![](https://img.yulucn.com/upload/f/2c/f2cc3bd6b689051ad72383d1669c0b99_thumb.jpg)
和
所以弦长|AB|=
![](https://img.yulucn.com/upload/e/59/e59925add07b8004b1c2b112410d2f5c_thumb.jpg)
=16
1年前
5