如图所示,在四棱锥
中,底面
是矩形,
平面
,
.过
的中点
作
于点
,连接
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/ec317199-3e9a-4111-9db8-b815b2dba378.png?resizew=154)
(Ⅰ)证明:
平面
;
(Ⅱ)若平面
与平面
所成的锐二面角的余弦值为
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a8067cc458cf12887177487c3cfb9c3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e7784be0caa2ffb58bbebf81fa127c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3533837e3d08c461dea031a44e5424d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/ec317199-3e9a-4111-9db8-b815b2dba378.png?resizew=154)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d0492b25f10ae45c39f8e9838519259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(Ⅱ)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193b5b41994c2a4dfa5bb0bc984061cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf31876698721a199c7c53c6b320aa86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
更新时间:2019-02-05 16:36:25
|
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解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,在多面体
中,
平面
为
的中点,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/26/eed13121-e113-4578-a1b8-bb21e85e7c99.png?resizew=166)
(1)证明:
;
(2)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dff800bc740bbdf43a8893586c601c01.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2620c7980ad06a97ed7336788005b53a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd108abaf2b7fc1d0239b28afcf4ae6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b67a9f29dc173b322e3acc4f8ae826d7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/26/eed13121-e113-4578-a1b8-bb21e85e7c99.png?resizew=166)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/316c97c5b6f7c0fbdf7b9e4b9fccb661.png)
(2)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6261790c66cc71ee3898afabad0c09f4.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在四棱锥
中,
平面ABCD,四边形ABCD为直角梯形,
,
,
,
,
,Q为PD的中点.
(1)求证:
平面ABQ;
(2)求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9060f03b9ee41d70d135b1e1a8902ce9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/829018a6ca0aff95d89e3f7cd943274e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3b10835116b9b777a666b438c907b49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be62ac0f5edb1eaebb5f491a7c30f97b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/29/c7371b22-a2c8-4812-ad5a-23ac01c531f1.png?resizew=138)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/534100c84d4561d2f156f7498e39e68e.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,直三棱柱
中,
,
分别是
的中点.
![](https://img.xkw.com/dksih/QBM/2022/4/11/2955750150627328/2958710143041536/STEM/7c4e036662f64bd480d5d0051a384e2e.png?resizew=280)
(1)求证
平面
;
(2)求二面角
的大小的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e31fc9e9075a05be23c9a7b4ccbdd020.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/927456b0989846a2f1573844bbaa2105.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/550bdcd1e7f40a0ae1f6bd6ce3c845e1.png)
![](https://img.xkw.com/dksih/QBM/2022/4/11/2955750150627328/2958710143041536/STEM/7c4e036662f64bd480d5d0051a384e2e.png?resizew=280)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d560542b646924eaf577480ac73281b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4a232e224922bf635c56075a9283bdd.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图所示,在棱长为
的正方体
中,
、
分别为
、
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/5233a36b-6143-4470-90c6-003a87c3a500.jpg?resizew=194)
(1)求证:
平面
;
(2)求平面
与平面
所成的锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.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/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/5233a36b-6143-4470-90c6-003a87c3a500.jpg?resizew=194)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f36df8302f33f07a69cef14c3b822902.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62a52848aff08399a36f217356007a4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
您最近一年使用:0次