题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030106-50069.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030106-34657.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030106-13017.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-79984.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-79429.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-14333.gif)
(Ⅰ)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-43907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-83230.gif)
(Ⅱ)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-69622.gif)
(Ⅲ)试确定点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-79984.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-52547.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-16187.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-13885.gif)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-85657.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-40896.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-22869.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-81978.gif)
而
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-24841.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-90437.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-43907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-83230.gif)
(Ⅱ)证明:因为
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030108-60199.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-69002.gif)
又因为
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-54239.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-65895.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-27958.gif)
而
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-79685.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-69622.gif)
(Ⅲ)当点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-79984.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-79429.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-52547.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-16187.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-13885.gif)
取DC的中点N,
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-56450.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-62549.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-22928.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-63861.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-14167.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-18265.gif)
又因为DC是面ABCD与面
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-95907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-95907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-54237.gif)
又可证得,
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-63861.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030109-62549.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-16187.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-42923.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-52547.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030107-16187.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030110-42923.gif)
解析
核心考点
试题【(12分)如图所示,在直四棱柱中,, ,点是棱上一点.(Ⅰ)求证:面;(Ⅱ)求证:;(Ⅲ)试确定点的位置,使得平面平面.】;主要考察你对空间几何体的结构特征等知识点的理解。[详细]
举一反三
A.垂直 | B.平行 | C.异面 | D.以上都有可能 |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030050-17955.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030051-76292.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030051-70383.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030051-44716.gif)
开图上的三点, 则正方体盒子中
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030051-34386.gif)
A.![]() ![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030046-52349.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030046-79404.gif)
A.3条 | B.4条 | C.6条 | D.7条 |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030040-77567.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030040-78221.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-54160.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-63802.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-15696.gif)
①若
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-58955.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-35445.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-90554.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-44591.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-43242.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-17410.gif)
③若
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-51617.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030041-35445.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-90554.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-51617.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-43242.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030042-90554.gif)
其中正确的命题是
A.②③ | B.①③ | C.①④ | D.③④ |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030033-99158.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030033-40089.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030033-20678.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030034-93140.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030034-65756.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030034-83846.gif)
则
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021030034-38054.gif)
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