题目
题型:不详难度:来源:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-77099.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-32721.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-82054.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-33964.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-34761.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-19072.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-60803.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-60803.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-14115.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-18488.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-79317.gif)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-91380.gif)
(2)求三棱锥
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-90822.gif)
(3)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-20667.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-14115.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-32964.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-82769.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-23137.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011902-68082.jpg)
答案
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011902-58887.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-82054.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011902-25068.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011902-23956.jpg)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011902-85275.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-82054.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-27185.gif)
而
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-34761.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-19072.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-31117.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-75054.gif)
∴
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-92899.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-59626.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-48835.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-59626.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-91380.gif)
(2)连接
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-57369.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-48183.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011900-79317.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-33964.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-48761.gif)
又
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011905-63254.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011905-25282.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011905-71483.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011905-45308.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011905-49247.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011906-96245.gif)
由已知及(1)得
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011906-54380.gif)
故
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011906-10050.gif)
(3)取
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011906-10360.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011906-62869.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011907-79367.gif)
∵
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-34761.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-19072.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011907-91741.gif)
又
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011907-53692.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-60803.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-14115.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011907-90034.gif)
又∵
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011907-24706.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-36462.gif)
所以
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-13172.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-82788.gif)
同理
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-85349.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-82788.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011909-28241.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-82788.gif)
又
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011909-96744.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011909-70625.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011909-45426.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-82788.gif)
∴当点
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-32964.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-60803.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-32964.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011859-14115.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011909-27862.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011901-82769.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011908-82788.gif)
解析
核心考点
试题【(本小题满分14分)如图,四边形为矩形,平面,,平面于点,且点在上,点是线段的中点。(1)求证:;(2)求三棱锥的体积;(3)试在线段上确定一点,使得平面。】;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
如图,在四棱锥P—ABCD中,底面ABCD是矩形,
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-79923.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-87623.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011903-80791.jpg)
(1)求证:
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011904-12348.gif)
(2)求直线CD与平面ACM所成的角的余弦值.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011704-72836.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011704-72156.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011704-46962.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011705-49951.jpg)
A.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011705-94112.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011705-55336.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011705-97110.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011706-12333.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011652-12116.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011652-17161.jpg)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011652-89779.jpg)
①求证PO丄平面ABCD
②求异面直线PB与CD的夹角;
③求点A到平面
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011653-75713.gif)
成的角为( )
A、
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011637-51336.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011637-61191.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011637-37157.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011637-16129.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011626-84428.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011626-94347.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011626-72793.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011627-57487.gif)
A.
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011627-89640.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011627-20543.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011627-52608.gif)
![](http://img.shitiku.com.cn/uploads/allimg/20191021/20191021011628-28548.gif)
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