如图,四棱柱
的底面是菱形,
平面
点
是侧棱
上的点,
,
(1)证明:平面
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/541a1dcba80a577cb2c6af4e7e8c9d6c.png)
(2)若P是
的中点,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/18a99be053c95aefbebe7460e50df572.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eac5405933e725cc5c970237d63d511.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db459a0c05bdc2ccefafd34a2793ccd1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e748663b134c6161ad31b4a279440cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed37af24eb3135379c9df3524a782cbe.png)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7d047313e1d1a47a3e9f3c3ef1677c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/541a1dcba80a577cb2c6af4e7e8c9d6c.png)
(2)若P是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e748663b134c6161ad31b4a279440cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c05bdbeb8a1e9b31bb905e92c15ca74.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/4d22a2c7-9af8-43bf-a42c-550de71d5447.png?resizew=162)
更新时间:2020-02-27 18:11:26
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在四棱锥
中,底面
是
且边长为
的菱形,侧面
为正三角形,且其所在平面垂直于底面
.
;
(2)若
为
边的中点,则能否在棱上找到一点
,使平面
平面
?并证明你的结论.
![](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/c6e0b64d25ddd18454f88e40c45d7d8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdfa54114f04a75b8c96165b3718ed7f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f6dd051db98c531f9ef18cdfd793f4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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2】如图,在
中,
平面
,
,
,
为棱
的中点,点
在棱
上.
![](https://img.xkw.com/dksih/QBM/2020/7/16/2507379745259520/2508050971729920/STEM/eb8a90ed22394c83889a4b44e515a402.png?resizew=105)
(1)若
,求证:
平面
;
(2)求证:平面
平面
;
(3)若二面角
的大小为120°,求异面直线
与
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/967f74b8993c61634ceed95edca05ffd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37bb4cadb426239b2e3551d94e1bc54f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://img.xkw.com/dksih/QBM/2020/7/16/2507379745259520/2508050971729920/STEM/eb8a90ed22394c83889a4b44e515a402.png?resizew=105)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcd72a32b01cde3803f106f00a83458c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9aa69a2247ad4d5231aa361349b12f97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10fc7991ea17d54ff5f4445ac5699463.png)
(3)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7554d7aa1dac63dbfa4a253b17fcd41c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在三棱柱
中,已知
,
,
,
.
![](https://img.xkw.com/dksih/QBM/2016/8/3/1572947995525120/1572948001923072/STEM/5410321d53d8407490931ae9ec6ca9f7.png?resizew=266)
(1)证明:
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883fc5e3faf39829d60804b59deb1730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41fd676c41d2d644928f014b0fea4689.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a9f99fb3252a4b3b7a62e8a675ddce9.png)
![](https://img.xkw.com/dksih/QBM/2016/8/3/1572947995525120/1572948001923072/STEM/5410321d53d8407490931ae9ec6ca9f7.png?resizew=266)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7870cee007535b979d35bc7feab75616.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f37656e410b600bc0019570dd16fb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/238c0f26c7f3a364a85d417494490527.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,在多面体ABCDEF中,四边形ABCD是正方形,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/aef0be5a-a7ad-4bbf-a200-f51e52b16765.png?resizew=167)
(1)求证:
平面CDEF;
(2)在线段BD上是否存在一点G,使得平面EAD与平面FAG所成的角为30°?若存在,求出点G的位置;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e41d3f7d55fcbaebc4e2450ac63a3dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/334fec9ec91596bf9d2b41568123715f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/67959df9e20e768def08e567db2cf579.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbd6348f7f46436e4fce4e87955f97ae.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/28/aef0be5a-a7ad-4bbf-a200-f51e52b16765.png?resizew=167)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f4c3f9dd5d0343597a7f58a1989b537.png)
(2)在线段BD上是否存在一点G,使得平面EAD与平面FAG所成的角为30°?若存在,求出点G的位置;若不存在,请说明理由.
您最近一年使用:0次