题型:解答题
难度:0.4
引用次数:1968
题号:11814132
如图所示,三棱锥
中,
平面
,
,平面
经过棱
的中点
,与棱
,
分别交于点
,
,且
平面
,
平面
.
![](https://img.xkw.com/dksih/QBM/2020/11/24/2599709883449344/2600750262992896/STEM/927da3d0-5917-45ae-a069-f5d062c8a1e4.png?resizew=181)
(1)证明:
平面
;
(2)若
,点
在直线
上,求平面
与平面
所成锐二面角的余弦值的最大值.
![](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/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08f8b463fcecf0a757f386db56e074d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c2b786c64e6a9ed2ec5670cde74f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://img.xkw.com/dksih/QBM/2020/11/24/2599709883449344/2600750262992896/STEM/927da3d0-5917-45ae-a069-f5d062c8a1e4.png?resizew=181)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/205a87cf1d5a8a943a272fe3409f2970.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb304d905125170bebfada27e7ed8960.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
更新时间:2020-11-25 21:02:51
|
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解题方法
【推荐1】四棱锥
中,四边形
是矩形,平面
平面
,四棱锥
的体积为
,
的面积为
,平面
平面
,
,
,
是
上的两个动点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/16/aa56f22d-031d-43a7-ab69-3d7fe5976708.jpg?resizew=251)
(1)求
到平面
的距离;
(2)当二面角
的平面角大小等于
时,求
的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c753cb1eb73fd8d136d00462970797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa7fb4bb4caccf79639a126064771da5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80c753cb1eb73fd8d136d00462970797.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c748e40ba21ac5063d3bccaa57ef278.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e742966e3711cfa53dce04022acf4bcc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d07ae0b4264da6a8812454ffd2f20d94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed5f0cfc1049f84a04c81bd213afb8d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/500df0e782bb081e608f4bc1d576afcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f8eeeea1c9652cacce976f8129cf520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/16/aa56f22d-031d-43a7-ab69-3d7fe5976708.jpg?resizew=251)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
(2)当二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddbaa6fbcea867ebc00bfe48454d8d5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79cd9d0d73549e2944578f3513631ce5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4452cdc95a45d4eb2456b47b3318ae1.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
【推荐2】如图,在直三棱柱
中,已知底面
为腰长为1的 等腰直角三角形,且
,
,
,
分别是棱
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/5fe44854-98bb-4f32-98e0-c5b4fe337db7.png?resizew=209)
(Ⅰ)求证:直线
平面
;
(Ⅱ)求直线
与平面
所成的角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed10df4140819d5451773a45de66201b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/462b1c65b1b233ab98a90c164c0968c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/5fe44854-98bb-4f32-98e0-c5b4fe337db7.png?resizew=209)
(Ⅰ)求证:直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88b90810b206fa24f92d84504169e02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(Ⅱ)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
您最近一年使用:0次
解答题-证明题
|
较难
(0.4)
解题方法
【推荐1】如图,在三棱锥
中,
,
,
的中点分别为
,点
在
上,
.
平面
;
(2)证明:平面
平面
;
(3)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d2d6eaafe1dea92077a00c13ef7123d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5b02f2bbc3dc60daf14a55b95b7efcd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb037c89cdcc909310ad713b48551402.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80b7e1ae8dd5ecd48253a797472fd67e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/57f9d682e5d3cc8573574d8d11636758.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7fe26dd3471224e87042fc3234e1ce5.png)
(2)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed292a4d27aa252b1259f45f86898e3e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c0bfeadcf17b2a45896071f07a4a5a.png)
(3)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b796bbaeb8450404c2d146283562006e.png)
您最近一年使用:0次
解答题-问答题
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较难
(0.4)
解题方法
【推荐2】如图,在四棱锥A-BCDE中,底面BCDE为平行四边形,平面ABE⊥平面BCDE,AB=AE,DB=DE,∠BAE=∠BDE=90°.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/6/61adbf92-a867-4d9e-bf0e-0a2abe7578e7.png?resizew=222)
(1)求异面直线AB与DE所成角的大小;
(2)求二面角B-AE-C的平面角的余弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/6/61adbf92-a867-4d9e-bf0e-0a2abe7578e7.png?resizew=222)
(1)求异面直线AB与DE所成角的大小;
(2)求二面角B-AE-C的平面角的余弦值.
您最近一年使用:0次