1 . 已知曲线C:
.
①曲线C的图像一定经过第三象限;
②若
为曲线C上一点,则
;
③存在
,
与曲线C有四个交点;
④直线
与曲线C无公共点当且仅当
.
其中所有正确结论的序号是______________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/324d45ba82fb2fa0380d57a517bf74c3.png)
①曲线C的图像一定经过第三象限;
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7775aa57ca0e62216f3039ed88dceed0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c07e792f906deeda22abc9e284759f2.png)
③存在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40e72f6b2ef3329828cb8fc873eeba7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c801656d9541fa6b3b3523911ee92b8.png)
④直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c801656d9541fa6b3b3523911ee92b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76e8a24e8e836a6dbac2f97bc340d702.png)
其中所有正确结论的序号是
您最近一年使用:0次
解题方法
2 . 如图,两个离心率相等的椭圆
与椭圆
,焦点均在x轴上A,B分别为椭圆
的右顶点和上顶点,过A,B分别作椭圆
的切线AC,BD,若AC与BD的斜率之积为
,则椭圆
的离心率为__________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f82a5421934348a612982ca099723b63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4455cb5ef8fa02f8740a01ea658ed7fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4455cb5ef8fa02f8740a01ea658ed7fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f82a5421934348a612982ca099723b63.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9237f95cb63d2e280e2ce8a4c5797255.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f82a5421934348a612982ca099723b63.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/5/2e501bd7-e0bd-4501-8f01-eb270d83ceff.png?resizew=177)
您最近一年使用:0次