1 . 已知椭圆
的方程为
.
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/d0b1f36d-b345-4b0d-a430-34a4d6718812.png?resizew=237)
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/5746b78d-f94b-488f-abce-a1cad298b5e8.png?resizew=236)
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/d4ba530b-f4a7-4281-ac34-ada03587e915.png?resizew=264)
(1)设
是椭圆
上的点,证明:直线
与椭圆
有且只有一个公共点;
(2)过点
作两条与椭圆只有一个公共点的直线,公共点分别记为
、
,点
在直线
上的射影为点
,求点
的坐标;
(3)互相垂直的两条直线
与
相交于点
,且
、
都与椭圆
只有一个公共点,求点
的轨迹方程.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/271e595c257e4c0ade90a9bbbf0e6b0d.png)
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/d0b1f36d-b345-4b0d-a430-34a4d6718812.png?resizew=237)
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/5746b78d-f94b-488f-abce-a1cad298b5e8.png?resizew=236)
![](https://img.xkw.com/dksih/QBM/2021/5/2/2712321353637888/2718228101832704/STEM/d4ba530b-f4a7-4281-ac34-ada03587e915.png?resizew=264)
(1)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7bc97d4acc37ccb7480571754737cbc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da744f1fe4ccafc57429536ff249ecd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
(2)过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6fcc80c8f221bfd1c575b7c95fbe66b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
(3)互相垂直的两条直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e9b0f5f44abbc6544a2f672b025b013.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f6f17bc385bafb37e8f964e5eb99cd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
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解题方法
2 . 已知直线
(a为常数,
,…),点
是
与
的交点,则数列
的前20项和为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fd4a4396b87816c1548e33bc1a03c00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/750335e0a1896eb270407e86335a85a2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a44042d110ad8bf676c2785c2b1f9a04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c34517f479fb08f6096d2fb0362f3ad0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c7c5e7bd6bac51402ffa04b4144ec78.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
A.320 | B.360 | C.590 | D.600 |
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