题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-61729.gif)
求证:当
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-77389.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-58856.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-34351.gif)
答案
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191736-72984.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191736-60389.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-58856.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191736-74323.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191736-65001.gif)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-77389.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191737-82112.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191737-37685.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-58856.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191737-24401.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191737-82961.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191737-49563.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191738-97034.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191738-21384.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191738-83414.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191738-84713.gif)
(1)当
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191739-90802.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191739-24159.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-34351.gif)
(2)当
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191739-64098.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191738-84713.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-34351.gif)
故当
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-77389.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-58856.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191735-34351.gif)
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191720-51826.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191720-90182.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191720-35285.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191720-20233.gif)
(2)求BP与平面A
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191720-75382.gif)
(3) 求二面角P-AB-D的大小.
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191710-93231.gif)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191704-36236.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191704-42718.gif)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191656-72247.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191656-71764.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191653-13191.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191653-85616.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191653-96681.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191653-53448.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191020/20191020191653-45575.gif)
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