如图,四面体
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b40c7bdf792b7139e66f193fb7393ac4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/b57dd048-57ea-46e7-a9c6-98785ba241b9.png?resizew=138)
(1)证明:平面
⊥平面
;
(2)若
,
分别是棱
的中点,过
三点的平面分此四面体为两部分,求这两部分体积之比.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b40c7bdf792b7139e66f193fb7393ac4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/13/b57dd048-57ea-46e7-a9c6-98785ba241b9.png?resizew=138)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4eb7e9ad5486cf1c5e506b20c5469e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce519312a849963b376c202c3f9d7cf7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/94c905599045694c50d401bfc78c394f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4219e91ec82252dbef43c701271bc1dd.png)
更新时间:2021-05-18 11:43:42
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图所示,在多面体
中,四边形
,
,
均为边长为
的正方形,
为
的中点,过
的平面交
于点
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/14/acafb3c8-749b-4f92-be5c-2f228038fc8a.png?resizew=200)
(1)证明:
.
(2)求平面
与平面
成角的余弦值.
(3)直接写出三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16b6e1ec79fd5adf04c8a98df0745e26.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ebb05874eb3353d754af24c9974273e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8cfbc0b5a8fbde804bd8425a4b76d207.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53de67d55ead2f0347f902e6f9d5da42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e539f26ed5e0b20ff7220559324869a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/14/acafb3c8-749b-4f92-be5c-2f228038fc8a.png?resizew=200)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/59cccc15c7cb2402341af1d5e3dd14bd.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b237ef19a4f4d26c3e32957574f149a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)直接写出三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8964550c7fc31d982b1534e884ad6f52.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,已知菱形
和菱形
所在的平面互相垂直,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/d22bfffc-5aa3-47f4-a95a-98c436cb6a64.png?resizew=220)
(1)求证:
平面
;
(2)若
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8332a0431b051fbae01719c87e730619.png)
,求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bbc56d42b003cbcb1fbe5c50e55b26b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/d22bfffc-5aa3-47f4-a95a-98c436cb6a64.png?resizew=220)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40f44f2b2f82a9126223138972850aa2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af68a7bf0da4f7c6f739d2e2461ad9b7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8332a0431b051fbae01719c87e730619.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac1a63ab608517bb10aa036783dfb51f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/820a55066be63da11d346175942b09aa.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1】如图,在三棱锥D-ABC中,已知△BCD是正三角形,AB⊥平面BCD,AB=BC=a,E为BC的中点,F在棱AC上,且AF=3FC.
(1)求三棱锥D-ABC的体积;
(2)求证:平面DAC⊥平面DEF;
(3)若M为DB中点,N在棱AC上,且
,求证:MN//平面DEF.
(1)求三棱锥D-ABC的体积;
(2)求证:平面DAC⊥平面DEF;
(3)若M为DB中点,N在棱AC上,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2239d3ef65845a7855c84932428bf079.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/28/ced31c5a-59bf-4ee2-891b-1a112da039a0.png?resizew=237)
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2】在如图1所示的梯形ABCD中,已知
,E为BC的中点,将△DEC沿DE折起,得到如图2所示的四棱锥,且此时
的体积最大.
![](https://img.xkw.com/dksih/QBM/2022/4/2/2949261268738048/2950748027969536/STEM/ca9987d73ae1447180dffbe4a32a3982.png?resizew=433)
(1)证明:平面
⊥平面
.
(2)若
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60cc42deee9761cf43f899bc18998142.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/912cfb0494804ef3c03991e894b6d4d6.png)
![](https://img.xkw.com/dksih/QBM/2022/4/2/2949261268738048/2950748027969536/STEM/ca9987d73ae1447180dffbe4a32a3982.png?resizew=433)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41104641f3e2260d00aeadf8fb8a078a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/692157e4e64f78fe0d293a1c7e343ccb.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da9b02a4ece39842989088e56b1d988b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0d8772aa893a9c1d40f714cb25701701.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41104641f3e2260d00aeadf8fb8a078a.png)
您最近一年使用:0次