如图,平面PAD⊥平面ABCD,ABCD为正方形,∠PAD=90°,且PA=AD,E、F分别是线段PA、CD的中点.
(Ⅰ)求证:PA⊥平面ABCD;
(Ⅱ)求EF和平面ABCD所成的角α;
(Ⅲ)求异面直线EF与BD所成的角β.
考点分析:
相关试题推荐
在△ABC中,内角A,B,C所对的边长分别是a,b,c.
(Ⅰ)若c=2,
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615013_ST/0.png)
,且△ABC的面积
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615013_ST/1.png)
,求a,b的值;
(Ⅱ)若sinC+sin(B-A)=sin2A,试判断△ABC的形状.
查看答案
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615012_ST/images0.png)
如图,动点P在正方体ABCD-A
1B
1C
1D
1的对角线BD
1上.过点P作垂直于平面BB
1D
1D的直线,与正方体表面相交于M,N.设BP=x,MN=y,则函数y=f(x)的图象大致是( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615012_ST/images1.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615012_ST/images2.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615012_ST/images3.png)
D.
查看答案
已知O,A,B是平面上的三点,直线AB上有一点C,满足
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615011_ST/0.png)
,则
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615011_ST/1.png)
等于( )
A.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615011_ST/2.png)
B.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615011_ST/3.png)
C.
![manfen5.com 满分网](http://img.manfen5.com/res/GZSX/web/STSource/20131024182905489261537/SYS201310241829054892615011_ST/4.png)
D.
查看答案
“函数f(x)(x∈R)存在反函数”是“函数f(x)在R上为增函数”的( )
A.充分而不必要条件
B.必要而不充分条件
C.充分必要条件
D.既不充分也不必要条件
查看答案
设a>1,若仅有一个常数c使得对于任意的x∈[a,2a],都有y∈[a,a
2]满足方程log
ax+log
ay=c,这时,a的取值的集合为
.
查看答案