解题方法
1 . 已知抛物线
的焦点坐标为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f99bddac58806e0024a1268378fe53d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/fe6afb9d-22fc-44cd-970e-d02511a7da08.png?resizew=188)
(1)求抛物线方程;
(2)过直线
上一点
作抛物线的切线切点为A,B
①设直线PA、AB、PB的斜率分别为
,求证:
成等差数列;
②若以切点B为圆心r为半径的圆与抛物线C交于D,E两点且D,E关于直线AB对称,求点P横坐标的取值范围.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82ea1be9b9b6bb12afa7e1ce703d1603.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f99bddac58806e0024a1268378fe53d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/30/fe6afb9d-22fc-44cd-970e-d02511a7da08.png?resizew=188)
(1)求抛物线方程;
(2)过直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/026808536f6b6d265c778e23836fbf13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eb6e8318d8bd0e6e051fc932cd22b25.png)
①设直线PA、AB、PB的斜率分别为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dca1726d463bd741c904abd9b6589056.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dca1726d463bd741c904abd9b6589056.png)
②若以切点B为圆心r为半径的圆与抛物线C交于D,E两点且D,E关于直线AB对称,求点P横坐标的取值范围.
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