如图,长方体
中,
,点M是棱
的中点,点E在
上,且
.
平面
;
(2)求平面
与平面
的夹角的余弦值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/273c489a7a63cfcf207e844ff28e2cfd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0761165f1176f3a5fe4f7b052832316d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed357ec154cc4d69f9cfd278ac2015d1.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/10fc7991ea17d54ff5f4445ac5699463.png)
更新时间:2024-05-25 19:20:22
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在四棱锥P﹣ABCD中,底面ABCD为矩形,平面PAD⊥平面ABCD,PA=PD=AD=2,AB=3.点M,N分别是AB,PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/ccb93fdb-c5e7-43ce-bae3-bed2cbf1dc7a.png?resizew=203)
(Ⅰ)求证:MN∥平面PAD;
(Ⅱ)求四棱锥P﹣ABCD的体积;
(Ⅲ)在棱CD上是否存在一点T,使得直线BT⊥PC?请给出你的判断,并说明理由.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/ccb93fdb-c5e7-43ce-bae3-bed2cbf1dc7a.png?resizew=203)
(Ⅰ)求证:MN∥平面PAD;
(Ⅱ)求四棱锥P﹣ABCD的体积;
(Ⅲ)在棱CD上是否存在一点T,使得直线BT⊥PC?请给出你的判断,并说明理由.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图①,在平面四边形
中,
,
,且
,将
沿
折起得到四棱锥
,如图②,且
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/423506c1-1b48-40aa-9f94-52b7b60af470.png?resizew=314)
(1)求证:
平面
.
(2)若
,
,问:在线段
上是否存在一点
使二面角
为
?若存在,求出线段
的长;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/481cb1bbc008a2d103e90b1e1efaf14f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5578cd49feb7c846f087b041371c3875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1f28ca4930b132289a485903ad9f1b57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5830322dd2824ed012a68f1a2bd9c742.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/423506c1-1b48-40aa-9f94-52b7b60af470.png?resizew=314)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d27ff0b39832f094ec51e28721d739.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/853cf489108a0c0104d3c3b1fa04cf86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/305a88d4e0249bd16d48eda01331d2d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fe3645167d922512d172875c2ef833ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15615de1a6df206dbd081251f676578e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8e5f736b1195fef1d2d300168a795f1.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,在几何体
中,
平面
,
平面
,
,又
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/3/1193dade-b6a0-420b-afa8-d31c1b090677.png?resizew=210)
(1)求
与平面
所成角的正弦值;
(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/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07792540180faa3a6208aad83183407a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c76d296e1cf0e421b3969c70064f6fcd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d2a74b2ba83f6d1cde9133212f38823.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/3/1193dade-b6a0-420b-afa8-d31c1b090677.png?resizew=210)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2bc5e50b8dfa02601c70822252854a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9c9cfa597b444b5c9dbae7a825a695.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9c9cfa597b444b5c9dbae7a825a695.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47fd1271a0085baf9f8f5ab519d0098f.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,在三棱锥
中,
底面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/2018/12/14/2096621831987200/2098950440140800/STEM/d7ae1032fcb3452a808a3450d882b880.png?resizew=199)
(1)证明:平面
平面
;
(2)若三棱锥
的体积为
,且
,求平面
与平面
所成锐二面角的余弦值.
![](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/2e4f0c1c9cca0555906d8a53e1a6803d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb2a990a387de2395358b2f41f304f2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab028119fe9e393433a1ae68e4cb9292.png)
![](https://img.xkw.com/dksih/QBM/2018/12/14/2096621831987200/2098950440140800/STEM/d7ae1032fcb3452a808a3450d882b880.png?resizew=199)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78a3fd5284e160896f07ce367645fd04.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddfe0ccf24d760c77535a70c92dad145.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31da7291140e430a11e2a10cc6cdefbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36c4559d27e3905980d1a4f1856f07de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b37793a3a810e823e10c340986f55ddd.png)
您最近一年使用:0次