题目
题型:不详难度:来源:
.如图,在△
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075755-86138.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075755-44219.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075756-77224.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075756-20635.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075756-79446.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075756-12786.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075757-70770.png)
C.
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075757-59631.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075757-92923.png)
答案
解析
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075757-79373.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075758-18323.png)
点评:此题中BD、DC、BD三条线段无法构成三角形
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075747-27657.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075747-38539.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-36397.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-14450.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-16632.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-36397.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-95898.png)
(Ⅰ)求异面直线与所成角的余弦值;
(Ⅱ)求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075749-83103.png)
(Ⅲ)设
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075749-11620.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075749-42989.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075749-57507.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075748-36397.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075750-53228.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075750-71319.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075750-95941.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075750-28953.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075728-64270.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075729-13076.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075729-44311.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075729-96934.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075729-27907.gif)
⑴ 设
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075730-12711.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075730-25264.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075730-50166.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075730-60927.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075730-78540.gif)
求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075731-51829.gif)
⑵ 若点
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075731-22270.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075731-71731.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075731-69952.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075728-64270.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075721-46877.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075721-84413.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075722-87931.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075721-46877.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075718-84986.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075718-96819.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075709-86859.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075709-32196.png)
⑴异面直线
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075710-75721.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075710-42933.png)
⑵四面体
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022075710-36150.png)
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