抛物线
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153012_ST/0.png)
的焦点坐标是
.
考点分析:
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双曲线x
2-y
2=2010的左、右顶点分别为A
1、A
2,P为其右支上的一点,且∠A
1PA
2=4∠PA
1A
2,则∠PA
1A
2等于( )
A.无法确定
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153011_ST/0.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153011_ST/1.png)
D.
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到两互相垂直的异面直线的距离相等的点,在过其中一条直线且平行于另一条直线的平面内的轨迹是( )
A.直线
B.椭圆
C.抛物线
D.双曲线
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设椭圆
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153009_ST/0.png)
和双曲线
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153009_ST/1.png)
的公共焦点分别为F
1,F
2,P是两曲线的一个交点,则cos∠F
1PF
2的值为( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153009_ST/2.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153009_ST/3.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153009_ST/4.png)
D.
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如果椭圆
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131101222758263715360/SYS201311012227582637153008_ST/0.png)
的弦被点(4,2)平分,则这条弦所在的直线方程是( )
A.x-2y=0
B.x+2y-4=0
C.2x+3y-12=0
D.x+2y-8=0
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下列命题中真命题的个数为( )
①命题“若x
2+y
2=0,则x,y全为0”的逆命题;
②命题“全等三角形是相似三角形”的否命题;
③命题“若m>0,则x
2+x-m=0有实根”的逆否命题;
④命题“在△ABC中,a、b、c分别是角A、B、C所对的边长,若∠C=90°,则c
2=a
2+b
2”的逆否命题.
A.1
B.2
C.3
D.4
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