题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043526-74199.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043526-79843.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043526-41361.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043526-74199.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043527-52271.gif)
正三角形,
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043527-12267.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043527-84025.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-35122.gif)
(Ⅰ)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-28876.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-96774.gif)
(Ⅱ)求证:平面BCE⊥平面
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-62066.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-88493.gif)
答案
解析
∵F为CD的中点,
∴FP∥DE,且FP=
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-65426.gif)
又AB∥DE,且AB=
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043528-65426.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043529-53079.gif)
∴ABPF为平行四边形,∴AF∥BP.…………4分
又∵AF
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043529-64612.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043529-46844.gif)
∴AF∥平面BCE…………6分
(Ⅱ)∵△ACD为正三角形,∴AF⊥CD
∵AB⊥平面ACD,DE//AB
∴DE⊥平面ACD 又AF
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043529-46844.gif)
∴DE⊥AF
又AF⊥CD,CD∩DE=D
∴AF⊥平面CDE …………10分
又BP∥AF ∴BP⊥平面CDE
又∵BP
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043529-46844.gif)
∴平面BCE⊥平面CDE …………12分
核心考点
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043516-59325.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043516-55018.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043516-69280.gif)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043516-55181.gif)
(2)求二面角A-SD-P的大小.
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043517-38762.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043500-79025.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-43907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-16284.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-89934.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-55602.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-25400.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043501-44364.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043502-20621.gif)
(Ⅰ)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043502-57899.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043502-20973.gif)
(Ⅱ)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043502-77073.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043503-42505.gif)
(Ⅲ)求三棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043503-75750.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043446-24948.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043446-78785.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043446-31202.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043447-81984.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043447-87253.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043447-76074.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043448-12785.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043448-76576.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043448-55776.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043448-24316.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043448-11961.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043449-83610.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043449-15874.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043449-93720.gif)
求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043449-73237.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043450-25383.gif)
(Ⅰ)证明:BN⊥平面C1B1N;
(Ⅱ)设直线C1N与平面CNB1所成的角为
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043438-23244.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043438-23244.gif)
(Ⅲ)M为AB中点,在CB上是否存在一点P,使得MP∥平面CNB1,若存在,求出BP的长;若不存在,请说明理由.
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043439-75782.jpg)
(1)求证:PB//平面AEC;
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043434-83459.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043434-20887.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043434-12186.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191106/20191106043434-20218.jpg)
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