如图,四棱锥
的底面是边长为1的正方形,侧棱
是四棱锥
的高,且
,
是侧棱
上的中点.
![](https://img.xkw.com/dksih/QBM/2020/12/29/2624712984223744/2628113782939648/STEM/838403b8-9bd3-4ad7-a125-56428b0f167d.png?resizew=222)
(1)求证:
平面
;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.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/2020/12/29/2624712984223744/2628113782939648/STEM/838403b8-9bd3-4ad7-a125-56428b0f167d.png?resizew=222)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bb178784aa857d4d4683e650273f054.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/926584088b939200d88e64318f2d4e6c.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c10c16d2d9d22c4b34ddd965e26aa0d7.png)
更新时间:2021-01-03 12:54:05
|
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解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在几何体
中,四边形
是菱形,
,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458329127239680/2458775724834816/STEM/0fd116d4b30e41bf89364a32455dc485.png?resizew=250)
(1)求证:
;
(2)若
,
,求三棱锥
和三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71ff3faa7ff8e9b8d323b090b38aefff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10df84d553a8826a7ce9bff4bf0d95b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d62d30d732c3c6ee3f0dd66d7059356.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e4e363bfd418579e6229230df034bbc.png)
![](https://img.xkw.com/dksih/QBM/2020/5/8/2458329127239680/2458775724834816/STEM/0fd116d4b30e41bf89364a32455dc485.png?resizew=250)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5621c78ba894e47b6161e27a664093a0.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b60692f95a2eb21e1da89eba8d1dfee.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2b67046592a3153a442165064287fcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d435a91c0447826d31158be0ce5a9e6d.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,四边形ABCD是边长为1的正方形,
平面ABCD,
平面ABCD,且
,E为BC中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/09ae6091-e25e-4689-bdae-689c70daad96.png?resizew=162)
(1)求四棱锥A—BDMN的体积;
(2)求点C到平面AMN的距离;
(3)在线段AN上,是否存在点S,使得
平面AMN?若存在,求线段AS的长,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f2cc6f154df30137d16d6b77dc5c480.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9c7510c8073f55615a7075eef937363.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5254a8bb97154dc16c9435ef00ff5818.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/3/19/09ae6091-e25e-4689-bdae-689c70daad96.png?resizew=162)
(1)求四棱锥A—BDMN的体积;
(2)求点C到平面AMN的距离;
(3)在线段AN上,是否存在点S,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c8b8ce66c0bd8d48dde9a30c8caffa9.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐1】已知四棱锥
中,
平面
,底面
是菱形,且
.
,
、
的中点分别为
、
.
(1)求证
.
(2)求二面角
的余弦值.
(3)在线段
上是否存在一点
,使得
平行于平面
?若存在,指出
在
上的位置并给予证明,若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.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/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05740f0c6071846227dc0ec177ad15e8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aef872df43521c02cfce3e51ca20330f.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/281177cc5c7e6294a474dc64ee02aa29.png)
(3)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8875ff2aff9d8790c55fbd5bcf41914b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/4/f639e5a5-2a72-4b20-a5c9-1d74a392fc03.png?resizew=196)
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】如图,正方形ABCD对角线的交点为O,四边形OBEF为矩形,平面
平面ABCD,G为AB的中点,M为AD的中点.![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2273ae1ee99cec9c1304323bc9ebf75f.png)
平面ECG.
(2)若
,求点M到平面ECG的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd2da6efea58f84064d26ebe2a8d72a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2273ae1ee99cec9c1304323bc9ebf75f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a77f26a7be722e00baa984f769ec8d4.png)
您最近一年使用:0次