如图,在长方体
中,
,
,点P在棱
上移动.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/3ed0915d-ff2d-4f8a-9b30-e1629787dbb8.png?resizew=231)
(1)证明:
;
(2)
等于何值时,二面角
的大小为
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7d64fc81c857b124268609a8beb77b6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/3ed0915d-ff2d-4f8a-9b30-e1629787dbb8.png?resizew=231)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a028053687dfb26f2f0632f1a5ce1e9.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20a541b81584a032f571159ea152c85a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcca9b044ed445b10e2ea3ca8c05f79d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
更新时间:2020-03-20 12:25:07
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图,已知四棱锥
中,
,
,
,
平面
,平面
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/1/6297a192-b14e-4f8d-a374-57068a036435.png?resizew=121)
(1)证明:
;
(2)若
,且
,
为
的重心.求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efeadd146662b5d8fe14a424138ef751.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5beb1af9d2ffb7d0089dec2c1af554da.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ff27eea7545bb06f9472f91290c54e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/4/1/6297a192-b14e-4f8d-a374-57068a036435.png?resizew=121)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb8c91e4c85a9da7f54b2237d870a50d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06a2ab6940dca62be1f3b2b5f8531990.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f944f78358763be992bb3d55fff12f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abf80148409afb32ced0b4f59f1ba709.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
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,
是以
为直径的半圆
上一点,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/6663f8aa-945e-4a52-81bf-6f2429ae9ee1.png?resizew=142)
(1)求证:
平面
;
(2)若
,
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c309e58bf083bad13abd549720a63a22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b13d28cb7181257cf732af4b615fc47d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/6663f8aa-945e-4a52-81bf-6f2429ae9ee1.png?resizew=142)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dbb78cdb972880c4a69ef564f2ccfcbd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6527c0ba31da7c6e44f2067d34a6c65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca6d1c5eace748465b2dad5065f5111c.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】已知四边形
,
,
,将
沿
翻折至
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/ce972e53-2568-418e-9861-e8842e8aa2fe.png?resizew=340)
(Ⅰ)若
,求证:
;
(Ⅱ)若二面角
的余弦值为
,求
与面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bba797c9497b139a93da88f88a768560.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb120e9e138816a803d4690ab6c3863.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fbfcae2cecc98e2d6c16dde6d3ec1c1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/3/ce972e53-2568-418e-9861-e8842e8aa2fe.png?resizew=340)
(Ⅰ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/62974d34de3a12418d6b700420afd1b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4710f75c66f19825a3e44b48f78bbac.png)
(Ⅱ)若二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9f1e2b86f4eca37c72011d3dffb0c9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/602baac86c2b1668ecdfadc8a5948885.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐1】已知在直角梯形
中,
,
,将
沿
折起至
,使二面角
为直角.
![](https://img.xkw.com/dksih/QBM/2018/2/18/1885130276536320/1888400227106816/STEM/2e16f08a-14b5-4421-9eb2-8bdce1add064.png)
(1)求证:平面
平面
;
(2)若点
满足
,
,当二面角
为45°时,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/889c99936ced6284514c7e5ee45c8142.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41aba1711910c6f533cc94319104f4fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/466ac9f2a8ad5825511c944f2e63be6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/70bf483b3b680bb4547513b912fd4c35.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c88a11128d8f44ccc4f3d1cfdd7a9291.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/282d4a8c3476b2b81e3fd73898e64539.png)
![](https://img.xkw.com/dksih/QBM/2018/2/18/1885130276536320/1888400227106816/STEM/2e16f08a-14b5-4421-9eb2-8bdce1add064.png)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06123e81c41198c76a3335757fac2c93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a4ab3caf58a6673195e333b14168c67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5213d1b56db71a731475c45572982df4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64785e4401e1d79632e360fd3626ed62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
您最近一年使用:0次
解答题-问答题
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(0.65)
名校
【推荐2】在如图所示的几何体中,
平面
,四边形
为等腰梯形,
,
,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/2018/5/22/1950763061190656/1952715129847808/STEM/ad6b1e1f-052c-450e-a622-9f73a7a14ff8.png)
(1)证明:
;
(2)当二面角
的余弦值为
时,求线段
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed04b01505bbd8a4ac0bc12e46f23bf6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4d34ac97b116fc5c4e99d07dda1c50b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68dfd32a77c3615069ad1e7eb5b226a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c62cca87325b32db22204f7cfa6cbb2.png)
![](https://img.xkw.com/dksih/QBM/2018/5/22/1950763061190656/1952715129847808/STEM/ad6b1e1f-052c-450e-a622-9f73a7a14ff8.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9f76925ed99b7172956319974258a9b.png)
(2)当二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19fa7ff056747ebdc342dc2ddf1b4b16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d83fb9ac8a18e78a4c56da79514b5ccb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cae70b8a9d2d2e96dea62c00ced04b9.png)
您最近一年使用:0次