解题方法
1 . 在平面直角坐标系
中,已知椭圆
的左、右焦点分别为
,且点
与椭圆C的上顶点构成边长为2的等边三角形.
![](https://img.xkw.com/dksih/QBM/2020/6/8/2480068559888384/2480296452120576/STEM/920490cef427499f84f0d64c8457a228.png?resizew=246)
(1)求椭圆C的方程;
(2)已知直线l与椭圆C相切于点P,且分别与直线
和直线
相交于点
.试判断
是否为定值,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ee31829d0d4d5f779a957d7df8058ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad523e69a1bf925e73a22900b9855df2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d2a97987f71835f519b462f5b8f5957.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d2a97987f71835f519b462f5b8f5957.png)
![](https://img.xkw.com/dksih/QBM/2020/6/8/2480068559888384/2480296452120576/STEM/920490cef427499f84f0d64c8457a228.png?resizew=246)
(1)求椭圆C的方程;
(2)已知直线l与椭圆C相切于点P,且分别与直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a089c207e39a24d0d82aa853ac2bbb8c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99c6875d552e9fff3c7d655f3a59b166.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7789a500686c7a73770404ead6af0590.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df51575d9a6b6c449c50d553c68ebb1.png)
您最近一年使用:0次
2020高三·江苏·专题练习
2 . 已知椭圆E:
+
=1(a>b>0)的离心率为
,焦点到相应准线的距离为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/391632be-5af3-4ef3-a312-e146bb15b6b8.png?resizew=186)
(1) 求椭圆E的标准方程;
(2) 已知P(t,0)为椭圆E外一动点,过点P分别作直线l1和l2,直线l1和l2分别交椭圆E于点A,B和点C,D,且l1和l2的斜率分别为定值k1和k2,求证:
为定值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7355be4fcbc3130a5951364a3be76d6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5268413295580cfda0755ab458b36b64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/860884c0017c8bceb5b0edff796c144f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/827ccf0c04aa941ba20d5f4c6068b46b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/391632be-5af3-4ef3-a312-e146bb15b6b8.png?resizew=186)
(1) 求椭圆E的标准方程;
(2) 已知P(t,0)为椭圆E外一动点,过点P分别作直线l1和l2,直线l1和l2分别交椭圆E于点A,B和点C,D,且l1和l2的斜率分别为定值k1和k2,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c2efd9f1d286d417d5596e4fa2b52a4.png)
您最近一年使用:0次