椭圆
+
=1和双曲线
-y2=1的公共焦点为F
1,F
2,P是两曲线的一个交点,那么cos∠F
1PF
2的值是( )
A.
B.
C.
D.
人气:375 ℃ 时间:2019-08-18 11:19:16
解答
设P是双曲线右支上的一点,设|PF
1|=m,|PF
2|=n.
则
,解得mn=3.
|F
1F
2|=4.
∴cos∠F
1PF
2=
=
=
=
.
故选:D.
推荐
猜你喜欢
- The film star_____both a TV series and some well-known films.A took part in B joined
- 8.7l是什么意思
- 22,24,27,32,39,( A 40 b 42 c 50 d 52我想问的这个数列后一个数减去前一个数之后的质数数列2,3,5,7.
- interior ministry是内政部的意思吗
- we often hear him play the violin at home 改为被动语态
- Two friends _____a picture together.a.have b.are having c.has d.is having
- 一些植物的叶脉相互交错,称为_,有些植物的叶脉大体上平行分布,称为_
- 一条鱼的重量等于它的四分之三加上四分之三千克,这条鱼重【 】千克