1 . 以下四个关于圆锥曲线的命题中:
①设
、
为两个定点,
为非零常数,
,则动点
的轨迹为双曲线;
②过定圆
上一定点
作圆的动弦
,
为坐标原点,若
则动点
的轨迹为椭圆;
③方程
的两根可分别作为椭圆和双曲线的离心率;
④双曲线
有相同的焦点.
其中真命题的序号为________ .(写出所有真命题的序号)
①设
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/e41105eb63b149e49b30d6ac962c08a3.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/5d3820140060404c90332e226ca0cfe1.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/0b89f655331a44b58f650fea035be439.png?resizew=13)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db429aa080d7c56eeac7a83f5ea7eb1f.png)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/ba10ed8a3a0b4fb3bf8dfe2febf9af44.png?resizew=16)
②过定圆
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/d23aa30797604e9cb6bb077bfecedd17.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/e41105eb63b149e49b30d6ac962c08a3.png?resizew=16)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/a64346ff9b50464c8cadd79b3553c7fa.png?resizew=27)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/0125600dc0ac48f19e3876b0e6318c3d.png?resizew=16)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18c0d52f7a06e016a827c8639b76cd3.png)
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/ba10ed8a3a0b4fb3bf8dfe2febf9af44.png?resizew=16)
③方程
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/fedf1ab1fecf4670ae200c37fe341395.png?resizew=108)
④双曲线
![](https://img.xkw.com/dksih/QBM/2011/11/21/1570357662908416/1570357668241408/STEM/d564972a103e4d7cb294f9296e67f20c.png?resizew=203)
其中真命题的序号为
您最近一年使用:0次
11-12高二上·广东揭阳·期末
2 . 已知
是双曲线
的两个焦点,点p在双曲线上,且满足
, 则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cda59d9787314cc9ae5b122a4847e24e.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d2a97987f71835f519b462f5b8f5957.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1892b7c3cd7bea116f532f66fba44662.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e457eb8c28f5ab11a879c954e15ee87e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cda59d9787314cc9ae5b122a4847e24e.png)
您最近一年使用:0次