如图,已知四边形
和
均为直角梯形,
,
且
,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/2017/1/19/1619466238443520/1619466239090688/STEM/f2541006f3b4496786f409f1c2468620.png)
(1)求证:
平面
;
(2)求平面
和平面
所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/693cd6179b2a92f03153ce12a0e86b95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cc3c947dc4deaf4eb5266772e43bee0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1057fba69b1554ceff580f73dbb28ff3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cf9a6db3571fa57bfa2d5e4d44c51b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/693cd6179b2a92f03153ce12a0e86b95.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/502fda7d60b3aa884b23094fac16ab63.png)
![](https://img.xkw.com/dksih/QBM/2017/1/19/1619466238443520/1619466239090688/STEM/f2541006f3b4496786f409f1c2468620.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e2fef2c0e49ecae8688ca60802310e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
更新时间:2017-02-08 11:15:24
|
相似题推荐
解答题-问答题
|
适中
(0.64)
【推荐1】已知在长方体
中,
分别是
的中点,
.
![](https://img.xkw.com/dksih/QBM/2016/10/6/1573055573901312/1573055579578368/STEM/6467c61bd80b4195aff68f701d99fb97.png)
(I)证明:
∥平面
;
(II)求直线
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8456cee87c4e22351affc28f3a73a0f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c88339e64acf5f1efeaea8e9c856ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4ef611321cd8b655f4307fa04704ee5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f3442496f4eb1901fa9e226e626268d.png)
![](https://img.xkw.com/dksih/QBM/2016/10/6/1573055573901312/1573055579578368/STEM/6467c61bd80b4195aff68f701d99fb97.png)
(I)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
(II)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193b5b41994c2a4dfa5bb0bc984061cc.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.64)
【推荐2】在四棱锥
,
平面ABCD,PA=2.
![](https://img.xkw.com/dksih/QBM/2015/3/26/1572034495954944/1572034501705728/STEM/10c6648844a545d6b8b5dcbdfc28c228.png)
(I)设平面
平面
,求证:
;
(II)设点Q为线段PB上一点,且直线QC与平面PAC所成角的正切值为
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54df3899ec44310cc91ce5033890d617.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e2f5b2d5fcd04b4ddc73a0dc600ced9.png)
![](https://img.xkw.com/dksih/QBM/2015/3/26/1572034495954944/1572034501705728/STEM/10c6648844a545d6b8b5dcbdfc28c228.png)
(I)设平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ebb72da110242e9fa3272e75fe82363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57c3a39145348a7f92fde1fddc05ea8b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96ebf94f30c42ae2fb65d19177e00b8a.png)
(II)设点Q为线段PB上一点,且直线QC与平面PAC所成角的正切值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d5989c84e320b504511f23eeb6e7357.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/450613b1e166a71f8c17c93f7dcbab97.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,正四棱柱
中,且
,点
分别是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/fec17ce4-b603-4faf-976a-aa658b52ab56.png?resizew=167)
(1)求直线
与直线
所成角的正切值;
(2)求平面
与平面
的夹角的余弦值;
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8edac2135706324de7174e7ced6476b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/012af0eae782b3aaad9f19c2ba93e70e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/fec17ce4-b603-4faf-976a-aa658b52ab56.png?resizew=167)
(1)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0e3334853138fb74687d66b1e45f2fd9.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e1c8a7da8c8473a060a686052018883.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96872cd6cd581ae8a861c7032e0257b4.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e1c8a7da8c8473a060a686052018883.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.64)
【推荐2】如图,已知长方形
中,
,
为
的中点.将
沿
折起,使得平面
平面
.
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/a8e593148d6647159977a13d95c874ee.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/f266ced348164779a5be72b476e3e076.png)
(Ⅰ)求证:
;
(Ⅱ)若点
是线段
上的一动点,问点E在何位置时,二面角
的余弦值为
.
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/777f0dcc5069443ea45df03b2840e98e.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/cb244a6444fb4aef963281240301b983.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/81bcbc87a5ae41fb9b7ec906dad2c6c0.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/09308938f9b347afa3b37142c0594e4e.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/ad613d5c8cbc432b86e3fa207e5bab88.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/32363a5fcb634e2187a13801a07deabf.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/f1553fb8d100449da795a84455f6a662.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/96c791cbd1ef4a9fbbab058eb09c6462.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/a8e593148d6647159977a13d95c874ee.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/f266ced348164779a5be72b476e3e076.png)
(Ⅰ)求证:
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/471c64d68736406aa7b8cebb16cad378.png)
(Ⅱ)若点
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/f8fd9e24828b426da77ce815e583903b.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/f66ef25bc0c94834bc0017f9de34e254.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/69957c07296141229dc587d0a512d1b5.png)
![](https://img.xkw.com/dksih/QBM/2015/6/15/1572122493845504/1572122499694592/STEM/6ac1591e52f64d4480e6ba4ae8aff07a.png)
您最近一年使用:0次