1 . 设抛物线E:
的焦点为F,从点F发出的光线经过E上的点
不同于E的顶点
反射,可证明反射光线平行于E的对称轴,这种特点称为抛物线的光学性质.过E上的动点A向准线l作垂线,垂足为B,过点A的直线m与E相切,设m交l于点C,连接CF,FB,FB交AC于点D,则以下结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79b3932717847eb0859019f07a7445ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
A.m平分![]() | B.![]() |
C.![]() ![]() | D.点D在定直线上 |
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2 . 设过抛物线
对称轴上的定点
,作直线
与抛物线交于
两点,且
,相应于点
的直线
称为抛物线的“类准线”.
(1)若
,求
的值;
(2)若点
是“类准线”
上任意一点,设直线
(其斜率都存在)的倾斜角依次为
,求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e42102c1c07562853219ca5918803a27.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fa4061a149f863b7ac4dd939f34ffc4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01c74a907dda6bb7d9d56d009d9df253.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac991b1781da9df3cb4e7f1524c05032.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/709887c8b7a179f0015b361b4979b939.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d9ca217fc5968a9b582b6cd8e898312.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c88d9142df6ba8e43c1a93bd04a1362.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c19fd0c317b0fd48e8ea57a6e793693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61ba63ad02b1d5af2982fac3d91eb15c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f44dbccbec6f1edfb1f82ecb7f148812.png)
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