如图所示,在三棱锥
中,
,
,
为
的中点,
垂直平分
,且
分别交
于点
.
![](https://img.xkw.com/dksih/QBM/2018/1/14/1860165904097280/1862216328994816/STEM/ccbf6737-8688-4bb0-83df-9375d0b3a75d.png?resizew=245)
(1)证明:
;
(2)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a6f37213648158634b24b8e39a19fd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09c94ff4614059e5e91ed304b150d886.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/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f5889fcf29e5d3a134ba9cee5e925f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://img.xkw.com/dksih/QBM/2018/1/14/1860165904097280/1862216328994816/STEM/ccbf6737-8688-4bb0-83df-9375d0b3a75d.png?resizew=245)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b63ce83647c1fe2fc7b32194d1b4114.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70734a8e672376bb0bd1522e229f86a2.png)
更新时间:2018-01-17 10:31:43
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,直三棱柱
的底面是边长为
的正三角形,点M在边BC上,
是以M为直角顶点的等腰直角三角形.
![](https://img.xkw.com/dksih/QBM/2015/7/20/1572187881750528/1572187887419392/STEM/a022a6ca8d3a4dfc9131857f3378a90e.png?resizew=197)
(1)求证:直线
∥平面
;
(2)求三棱锥
的高
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c21f920814c1c5e76d3f3b72bd22934.png)
![](https://img.xkw.com/dksih/QBM/2015/7/20/1572187881750528/1572187887419392/STEM/a022a6ca8d3a4dfc9131857f3378a90e.png?resizew=197)
(1)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46b91c857bbe3c4f0f08dd2a4124a96e.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a45bcecac150a0198a1ec16c67cd356.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图,在直三棱柱
中,点
是
中点,点
是
的中点,连接
.
(1)证明:
平面
;
(2)若
,
,
,求二面角
的余弦值的大小.
![](https://img.xkw.com/dksih/QBM/2013/10/22/1571374224465920/1571374230339584/STEM/e7468bc7e08544c99a1670f01b502503.png?resizew=305)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/126a3d8d69d4623cefbd444020e92db5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0218542daefa15910d5111b27e71f5b3.png)
![](https://img.xkw.com/dksih/QBM/2013/10/22/1571374224465920/1571374230339584/STEM/e7468bc7e08544c99a1670f01b502503.png?resizew=305)
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1】如图,在多面体
中,四边形
是矩形,侧面
是直角梯形,
,
与
交于点
,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/6/ad75b0d4-f4c9-4ede-8de4-70574cb156a9.png?resizew=187)
(1)证明:
平面
;
(2)若
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b312dab930cbbb9a4bb1a99f044dab73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ecc1cb55a57dde481f8dd07ab150676.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4ffb68a9ca3bf66788363bc89dab45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d6069b03d34138cd0f51b256185040c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2c3d2cba96f6f03520c0b3f6e4da03e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/6/ad75b0d4-f4c9-4ede-8de4-70574cb156a9.png?resizew=187)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a2f83ac39a73f4f01fb8068a0556fa8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/077c956ac0eb05cf120e14f17413dfa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccc3bf74119692ac98eb24fcfa2a3f9f.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2】如图,在四面体
中,E是线段
的中点,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/ec273443-bdba-42ed-9eaa-b88fa4d3ea5d.png?resizew=162)
(1)证明:
;
(2)求平面
与平面
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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bb80bf2994f71e7c74972725fd98573.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f5fc4ad65b723b6a8da4c8dac154e6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21519ccb36fd595bb21e6189d305ef1e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/13/ec273443-bdba-42ed-9eaa-b88fa4d3ea5d.png?resizew=162)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e7f2ab75abc366639a5ca25f6f3d951.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9a814b70236a108be5d6e7ff271fe92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/678b28fddb166d90878d24d6e5481080.png)
您最近一年使用:0次