如图,矩形ABCD的对角线AC,BD交于点O,
,
.沿AC把
折起,使二面角
为直二面角,求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ac451db3443cabb204f96c31fd4a02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4278d42a1b5b49af9fe6d5b531fa6b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b64c62436aa3581173ce9260d5c4ef89.png)
20-21高二·江苏·课后作业 查看更多[3]
更新时间:2021-12-05 00:03:03
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【知识点】 面面角的向量求法
相似题推荐
解答题-问答题
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【推荐1】在四棱锥
中,底面ABCD是矩形,
为BC的中点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/28/f85978d3-f058-46f4-b620-e768640abe5f.png?resizew=191)
(1)证明:
平面ABCD;
(2)若PC与平面PAD所成的角为30°,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6be2b61f4a38e2ee2c1a01e00b3ae6c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/676aab822f6b92aaf84cd688acb7050d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65c929fed1d514a112dab659d514dd9b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/28/f85978d3-f058-46f4-b620-e768640abe5f.png?resizew=191)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afb18c7c5391647214d4da31a88202d2.png)
(2)若PC与平面PAD所成的角为30°,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f09cf4f12bcfc80a91ebcbfc6e372ae6.png)
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解题方法
【推荐2】如图,四棱锥
的底面
为矩形,侧面
是边长为2的等边三角形,平面
平面
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/15/fdd08b81-e098-4ed4-bbae-9657fcae4e1c.png?resizew=245)
(1)求平面
与平面
的夹角的余弦值;
(2)在线段
上是否存在一点
,使得直线
与平面
所成角的正弦值等于
,若存在,确定点
的位置,若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea2c4cc37d6ba218107c9c5d820740fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b82fa8f506f8099ca06c36c706db479.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/15/fdd08b81-e098-4ed4-bbae-9657fcae4e1c.png?resizew=245)
(1)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c54d01623f09f23103f03ba1135fc6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00a28be4d5a16cf245f6fa7c4088fee4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c884b508394b3ab50734b584d9ec783c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/108fc9fdfe7b21273a30de970453a1b0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00a28be4d5a16cf245f6fa7c4088fee4.png)
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【推荐3】如图,在三棱柱
中,
平面
,点
,
分别在梭
和棱
上,且
为棱
中点.![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ef601ca1f9c4c031adab4ffed297f0.png)
平面
;
(2)从下面两个选项中选择一个作为条件,求二面角
的余弦值.
①
;②
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a8bfe2553e852df73185d017c0a62fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f91f0d1a4e368147e3783c9374461b3c.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/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d8379e02133be85a72747674b14f86f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ef601ca1f9c4c031adab4ffed297f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0278f9809e118b80c9946d9b9ae40c83.png)
(2)从下面两个选项中选择一个作为条件,求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/024d58baa25d2565912a9e6e3a06dbe2.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bffd657e48b15b9b54a55817e2c26b22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68884f80e717c6411347e9a7b4ada39a.png)
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