四棱锥S-ABCD中,侧面SAD是正三角形,底面ABCD是正方形,且平面SAD⊥平面ABCD,M、N分别是AB、SC的中点.
(Ⅰ)求证:MN∥平面SAD;
(Ⅱ)求二面角S-CM-D的余弦值.
(Ⅰ)求证:MN∥平面SAD;
(Ⅱ)求二面角S-CM-D的余弦值.
更新时间:2016-12-03 10:46:17
|
相似题推荐
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】在如图的空间几何体中,四边形BCED为直角梯形,∠DBC=90°,BC=2DE,AB=AC=2,CE=AE=
,且平面BCED⊥平面ABC,F为棱AB中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/2/4ecbc9c9-69d4-4259-85b2-6badf344032e.png?resizew=201)
(1)证明:DF⊥AC;
(2)求二面角B﹣AD﹣E的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/2/4ecbc9c9-69d4-4259-85b2-6badf344032e.png?resizew=201)
(1)证明:DF⊥AC;
(2)求二面角B﹣AD﹣E的正弦值.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐2】如图,在四棱锥
中,
平面
分别为
的中点.
平面
;
(2)若
,求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11f18c7418956adcf8ea13759236507d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddc0629aebb83da3017a7ecec0161e47.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d43ee0103b789698d981f768f0e5b9fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcf19a7f0dd0cdf59516ae585025110.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/487b14c446e989c68d0e148cc557dbf2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
真题
解题方法
【推荐1】如图,在四棱锥
中,底面
是边长为1的菱形,
,
底面
,
,
为
的中点.
(Ⅰ)求异面直线AB与MD所成角的大小;
(Ⅱ)求点B到平面OCD的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06a5faf3cbb633fc4294c8ce703c64c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d6baf49925a5bcb359b542d45067c81.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4317430d5a2b61d9a2a88b73e7d7ad39.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9774f83067ed956a551bc41adcce0469.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
(Ⅰ)求异面直线AB与MD所成角的大小;
(Ⅱ)求点B到平面OCD的距离.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/16/e20085dd-f55b-4e1e-bc28-b27ab2a3b44c.png?resizew=170)
您最近一年使用:0次
解答题-证明题
|
适中
(0.64)
【推荐2】已知
菱形
所在平面,点
、
分别为线段
、
的中点.
![](https://img.xkw.com/dksih/QBM/2015/2/5/1571979311325184/1571979317157888/STEM/751eb3cb1b954a59bfd4de685bee9d85.png)
(Ⅰ)求证:
;
(Ⅱ)求证:
∥平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/551e4cd76a93de89ea2750160fe74923.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/2015/2/5/1571979311325184/1571979317157888/STEM/751eb3cb1b954a59bfd4de685bee9d85.png)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8606472edf34185e67ab493af7e06f32.png)
(Ⅱ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b37793a3a810e823e10c340986f55ddd.png)
您最近一年使用:0次