在图1中,
,
,
为等边三角形,O为AC边的中点,E在BC边上,且
,沿AC将
进行折叠,使点D运动到点F的位置,如图2,连接FO,FB,FE,
.
(1)证明:
平面ABC.
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d9142db4dd2ef151bf3d4a63afb61e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb4957406b21df59fdf7fa184752287b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de01ca42a21f0cb44b2c914e092a0d85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c545be1051b20aea348bc99505c27022.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/2/0f9d71fd-47ab-4028-928c-d7a82185fead.png?resizew=298)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/befd9ccddb75aeb71cd1a008669f34da.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7289950468c026d5ceac17a79334dfe9.png)
23-24高三上·福建福州·期中 查看更多[3]
更新时间:2023-11-10 18:57:58
|
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解答题-问答题
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适中
(0.65)
名校
解题方法
【推荐1】如图,四棱锥
中,
平面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/787fc3bd-3bad-4590-b46f-0592f5f52026.png?resizew=155)
(I)证明:
;
(Ⅱ)若
是
中点,
与平面
所成的角的正弦值为
,求
的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e86986055c9919b375c8c3af4ae8df0d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e918b70b02a73685e3c536c7f380e2c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/787fc3bd-3bad-4590-b46f-0592f5f52026.png?resizew=155)
(I)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb5d56d8170b764b80a672cd6c861921.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4df730e937fb61b85054d316848b304.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
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解答题-证明题
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【推荐2】如图,在直三棱柱
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c06154cae3bf7a8ce5a1e97a7380875.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/883fc5e3faf39829d60804b59deb1730.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
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您最近一年使用:0次
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【推荐3】如图,在三棱锥
中,
,
,
两两互相垂直,
,
分别是
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/11/8a034a64-fdd7-4f98-88a6-279030b9dc3a.png?resizew=245)
(1)证明:
;
(2)设
,
,
和平面
所成角的大小为
,求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d78abbad68bbbf12af10cd40ef4c353.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/7/11/8a034a64-fdd7-4f98-88a6-279030b9dc3a.png?resizew=245)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bf271d6475f5305bc922677b4cfe28c.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a65b94de267eb6858634181642c65c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3427311203b1958b9ff89084c66a09a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca6d1c5eace748465b2dad5065f5111c.png)
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【推荐1】在三棱锥P﹣ABC中,AB=1,BC=2,AC
,PC
,PA
,PB
,E是线段BC的中点.
![](https://img.xkw.com/dksih/QBM/2020/1/4/2370068816748544/2371967322333184/STEM/380a6c65da1643fd8799e52c56410195.png?resizew=139)
(1)求点C到平面APE的距离d;
(2)求二面角P﹣EA﹣B的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd516e4b396722941982a389ee6e524c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ae65bdb69940a67a18d56ff02060b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd516e4b396722941982a389ee6e524c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a88baedfc1deeee9e85138abddfdd000.png)
![](https://img.xkw.com/dksih/QBM/2020/1/4/2370068816748544/2371967322333184/STEM/380a6c65da1643fd8799e52c56410195.png?resizew=139)
(1)求点C到平面APE的距离d;
(2)求二面角P﹣EA﹣B的余弦值.
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,在四棱锥
中,
是等边三角形,底面
是菱形,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/fa2266b7-d508-4c6f-b324-c062e94d28e0.png?resizew=158)
(1)证明:
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55a675310c8ba418e5a59beb7317e21e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea4f5eec0addba78f2e0cdfb7ecc59a6.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/fa2266b7-d508-4c6f-b324-c062e94d28e0.png?resizew=158)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdfa54114f04a75b8c96165b3718ed7f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff0a0c299356c26338d4153748e8a61d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33b7213d99a817bff19bcf740a0697c.png)
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