题目
题型:不详难度:来源:
在三棱锥ABCD中,平面DBC⊥平面ABC,△ABC为正三角形, AC=2,DC=DB=
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015846-84001.gif)
(1)求DC与AB所成角的余弦值;
(2)在平面ABD上求一点P,使得CP⊥平面AB D.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015846-39681.gif)
答案
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015846-58418.gif)
(2)(
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015846-42553.gif)
解析
核心考点
试题【必做题, 本小题10分.解答时应写出文字说明、证明过程或演算步骤.在三棱锥ABCD中,平面DBC⊥平面ABC,△ABC为正三角形, AC=2,DC=DB=,(1】;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
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015840-77741.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-69319.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-55928.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-69319.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-52773.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-44117.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015841-69319.png)
A.直线 | B.圆 | C.抛物线 | D.双曲线 |
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015842-61112.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015831-81219.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015831-73199.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015832-49116.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015832-20765.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015832-65055.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015832-85154.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015832-38203.gif)
(1)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-37588.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-24336.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-37588.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-92439.gif)
(2)求点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-37746.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015833-92439.gif)
(3)求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015834-57985.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015834-35144.gif)
如图,三棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015818-99084.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015818-64643.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015818-67098.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015819-77873.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015819-73383.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015819-26289.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015819-46317.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015819-49798.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015820-53438.jpg)
(1) 求证:侧面
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015820-38160.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015820-96650.gif)
(2) 求点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015820-57771.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015820-79943.gif)
(3) 求异面直线
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015821-93372.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015821-89634.gif)
已知:如图,长方体
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015759-29881.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015759-65835.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015759-13997.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015759-42987.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015800-42735.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015800-16387.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015800-79633.gif)
(1) 求异面直线
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015800-65121.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015800-15978.gif)
(2) 证明
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015801-15334.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015801-51214.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015801-19446.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015801-25322.gif)
(3) 求二面角
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015802-58907.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015802-58678.gif)
如图,在四棱锥P-ABCD中,底面ABCD是矩形,M、N分别为PA、BC的中点, PD⊥平面ABCD,且PD=AD=
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015740-44880.gif)
(Ⅰ)证明:MN∥平面PCD;
(Ⅱ)证明:MC⊥BD;
(Ⅲ)求二面角A—PB—D的余弦值.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021015740-14036.jpg)
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