1 . 给出下列四个命题
已知P为椭圆
上任意一点,
,
是椭圆的两个焦点,则
的范围是
;
已知M是双曲线
上任意一点,
是双曲线的右焦点,则
;
已知直线l过抛物线C:
的焦点F,且l与C交于
,
两点,则
;
椭圆具有这样的光学性质:从椭圆的一个焦点出发的光线,经椭圆反射后,反射光线经过椭圆的另一个焦点,今有一个水平放置的椭圆形台球盘,点
,
是它的焦点,长轴长为2a,焦距为2c,若静放在点
的小球
小球的半径忽略不计
从点
沿直线出发则经椭圆壁反射后第一次回到点
时,小球经过的路程恰好是4a.
其中正确命题的序号为______
请将所有正确命题的序号都填上
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e1c9ae241fd78126274c65e17990c88.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45dc12527b1ac520121e7e42b114c539.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a055d94c4c69a7f867c0e2b69bd8041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1996f60e2c55e0caa2b095ac23ab2b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ee51e2bac715aa1c5dbb4d109b9a115.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ec7369765a42dfa8ac1e16be9d1cf96.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c650fe55b7603f106c53ca2423451c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21bb38218bac3f428548d7070b699df4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1996f60e2c55e0caa2b095ac23ab2b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04fe34637dc2b288decdf7998b592f55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f82e415812cca9545611c0faa0c01b1c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93be9f8fb5fc2a0908a3389f08f6c57b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db444620748560d5b3e90cead81dc4ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a523345916a439fca79a5d56e3014b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4b56aef1fc3e2160072ebec70e413c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d8b8edd94bc4d5d517ec77e56800e41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a055d94c4c69a7f867c0e2b69bd8041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1996f60e2c55e0caa2b095ac23ab2b5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a055d94c4c69a7f867c0e2b69bd8041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a055d94c4c69a7f867c0e2b69bd8041.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a055d94c4c69a7f867c0e2b69bd8041.png)
其中正确命题的序号为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d71379442f28c038d367d49422cf90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/987517758fad59f6f695761deb2a5ebd.png)
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