已知正方体
,求证
(1)
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
(2)求平面
与平面
所成夹角的余弦值
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d26d8a9d64ad3c8cba28840b41ed7837.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf9628142422a4884bd59538da6d312.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4294ffdba16ae69fd03b13959d682aba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9c237015ab2c034ca97cbb3928f7f9b.png)
更新时间:2024-01-12 13:54:54
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相似题推荐
解答题-证明题
|
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解题方法
【推荐1】如图,已知四棱锥
的底面ABCD是边长为1的正方形,
,
,E是侧棱PC上的动点.
![](https://img.xkw.com/dksih/QBM/2021/10/12/2827787087249408/2831925777031168/STEM/6cca042d-b98f-4b7a-b1fa-0b517a24b7fb.png?resizew=257)
(1)求证:不论点E在何位置,都有
;
(2)若
平面BDE,求直线AE与平面BDE所成角的正弦值;
(3)在(2)的条件下,求点Р到平面BDE的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d618f2f945043c0fc4b2bb492206d4cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2899e607479d8d1c47d954ae9ebb7144.png)
![](https://img.xkw.com/dksih/QBM/2021/10/12/2827787087249408/2831925777031168/STEM/6cca042d-b98f-4b7a-b1fa-0b517a24b7fb.png?resizew=257)
(1)求证:不论点E在何位置,都有
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84be64d28b1623e71ad989f37336b1f2.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c2b786c64e6a9ed2ec5670cde74f86.png)
(3)在(2)的条件下,求点Р到平面BDE的距离.
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【推荐2】在四棱锥
中,
底面
,且
,四边形
是直角梯形,且
,
,
,
,
为
中点,
在线段
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/16/86cefce5-4510-4b3d-a576-19a19b7b5691.png?resizew=162)
(1)求证:
平面
;
(2)求直线
与直线
所夹角的余弦值;
(3)求点
到平面
的距离.
![](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/0b80ee363635d73f601654339028daec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1134c8e3440abb6cd385af2c169037fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae1e04eeb4de72e5750dae77bcb6f88a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8745717601cd14b46c2298919b41b502.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e65a3e478bb87d094e3a0af30dd10ae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.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/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adc90c2d45477e166b02359525f40aa6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/16/86cefce5-4510-4b3d-a576-19a19b7b5691.png?resizew=162)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f9fbdf06226a2365e120a88ea22e067.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fc5adb5eb60ae4435a12d93854066298.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/218054144a13435580cd132b9459546c.png)
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解答题-问答题
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适中
(0.65)
解题方法
【推荐1】如图,四棱锥
的底面是矩形,
平面
,
,
为
与
的交点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/c6e044d3-9349-4938-b279-a49d4db764b0.png?resizew=158)
(1)证明:三棱锥
,
体积相等;
(2)设
为
中点,
,
,
分别为
,
上的点,且
,当三棱锥
体积最大时,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99475d1687074a1ac87b6472be2a1964.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/3/c6e044d3-9349-4938-b279-a49d4db764b0.png?resizew=158)
(1)证明:三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6781fd321e792b2a3dfbb4e6558416ab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5402d4268ec1028e5307063539c10d7.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2cdba1337ec85fa9722cb4b320a82ae6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ffc2817fa590affb5a760a25dc65308.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73cbd27d06065f2ddd5cf5ccbe5bef48.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8976f23ebdcd77b6435f002e43b0f94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6819c533932173d8fdbc37302859991b.png)
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【推荐2】如图,三棱锥
及其正视图与俯视图如图所示.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/8f528d9e-33e5-4841-8da5-d2e45f032ad6.png?resizew=421)
(1)求证:
;
(2)若D是
的中点(未画出),求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/1/8f528d9e-33e5-4841-8da5-d2e45f032ad6.png?resizew=421)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1e4b16c2c6c9bd089da78122e9d2511.png)
(2)若D是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c909cd1b6f3fa1ec39eb245e8f5c11c.png)
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