题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032126-46111.jpg)
A.平面ABD⊥平面ABC | B.平面ADC⊥平面BDC |
C.平面ABC⊥平面BDC | D.平面ADC⊥平面ABC |
答案
解析
核心考点
试题【如图,在四边形ABCD中,AD∥BC,AD=AB,∠BCD=45°,∠BAD=90°,将△ABD沿BD折起,使平面ABD⊥平面BCD,构成三棱锥A-BCD,则在】;主要考察你对线线角等知识点的理解。[详细]
举一反三
①若α∥β,m⊂β,n⊂α,则m∥n;
②若α∥β,m⊥β,n∥α,则m⊥n;
③若α⊥β,m⊥α,n∥β,则m∥n;
④若α⊥β,m⊥α,n⊥β,则m⊥n.
上面命题中,所有真命题的序号为________.
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032112-55684.jpg)
(1)证明:平面PAB与平面PCD的交线平行于底面;
(2)求cos∠COD.
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032108-25570.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032108-37223.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032109-17086.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032109-23761.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032108-25570.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032109-17086.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032108-37223.png)
A.内心 | B.外心 | C.重心 | D.垂心 |
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032102-83818.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032103-80383.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032103-34173.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032103-11798.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032103-19321.png)
A.![]() ![]() ![]() ![]() ![]() ![]() ![]() |
B.若平面![]() ![]() ![]() |
C.若![]() ![]() ![]() |
D.若![]() ![]() ![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032050-62653.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-24480.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-13983.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-24480.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-57342.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-42127.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-33980.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-53882.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-44482.jpg)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032051-79022.png)
(2)求直线
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032052-57208.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022032052-68552.png)
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