题目
题型:不详难度:来源:
如图,已知四棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063935-49509.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-80404.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-60751.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-53410.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-60751.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-74292.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-68038.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-59896.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-60751.png)
(Ⅰ)证明:平面
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-13112.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-46432.png)
(Ⅱ)若
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-93757.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-15982.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063935-49509.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-49183.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-68182.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063938-99787.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063938-11226.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063938-16942.png)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063938-92487.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-13112.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-46432.png)
(Ⅱ)设三棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-15982.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063939-76353.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063939-75702.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063939-63499.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063939-13060.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063939-37517.png)
过
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063936-59896.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063940-76831.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063940-84566.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063940-75425.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063937-68182.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063940-68414.png)
设
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063941-32613.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063941-30353.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063941-62656.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063941-95980.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063941-43414.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063942-12166.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063942-76385.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063942-94166.png)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063942-55576.png)
解析
核心考点
试题【(本小题满分15分)如图,已知四棱锥中,平面平面,平面平面,为上任意一点,为菱形对角线的交点.(Ⅰ)证明:平面平面;(Ⅱ)若,三棱锥的体积是四棱锥的体积的,二面】;主要考察你对线线角等知识点的理解。[详细]
举一反三
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063930-34221.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063930-77183.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063930-57182.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063930-15295.png)
点,则PM的最小值为 ( )
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063921-65186.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063921-58475.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063921-68503.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063921-73136.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063922-21950.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063922-77682.png)
线
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063922-46039.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063922-52444.png)
A.![]() | B.![]() | C.![]() | D.![]() |
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063915-11596.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-67014.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-42661.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-80860.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-80860.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-85866.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063916-47859.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-80971.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-35988.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-51028.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-99365.png)
(1) 求证:侧面
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-54223.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-35988.png)
(2) 求侧棱
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-93250.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063904-35988.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063905-70619.png)
已知
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063859-23617.png)
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063859-30998.png)
(1)证明:
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063859-31798.png)
(2)求二面角C—DB—A的正切值。
![](http://img.shitiku.com.cn/uploads/allimg/20191022/20191022063900-82098.png)
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