在矩形
中,已知
,
,
为
的三等分点(靠近A点),现将三角形
沿
翻折,记二面角
,
和
的平面角分别为
,则当平面
平面
时
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/efc6e4b936d7a800e839a30c3839574d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ddb7c2ca1b6bee86cb24fed02e40da2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a424b50eaeafa6f302ffd95476cb86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c123937cd5c0769090771598d6aee7c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6f1d9f040e7c4c6e4d9e8c0ed4f44984.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a73bb7c05c513441ff37e6a8dea131b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61ba63ad02b1d5af2982fac3d91eb15c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcf6dc837ae85207789b94d109c5c2eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f9e5a462c0ca3b9e2c603750a3b433b.png)
A.![]() | B.![]() | C.![]() | D.![]() |
19-20高二下·浙江·期中 查看更多[3]
浙江省浙北G2(湖州中学、嘉兴一中)2019-2020学年高二下学期期中数学试题(已下线)第01章 空间向量与立体几何(B卷提高卷)-2020-2021学年高二数学选择性必修第一册同步单元AB卷(新教材人教A版)(已下线)期中重难点突破专题03-【尖子生专用】2021-2022学年高二数学考点培优训练(人教A版2019选择性必修第一册)
更新时间:2020-05-26 08:54:45
|
【知识点】 二面角的概念及辨析
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【推荐1】正三棱柱
(底面是正三角形,侧棱垂直底面)的各条棱长均相等,
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的中点,
、
分别是
、
上的动点(含端点),且满足
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/a7107c4d-2aeb-4747-a560-4a80e03e58f4.png?resizew=144)
①平面
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②三棱锥
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③
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④平面
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/2/a7107c4d-2aeb-4747-a560-4a80e03e58f4.png?resizew=144)
①平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3834847059043d4677c6be33d9a81141.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
②三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c4823ae5a2befbb275467c3604af74c.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88c043c1a8696b06caf7d4bcd0d81e8c.png)
④平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/193b5b41994c2a4dfa5bb0bc984061cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d6888702c4e6a983a3fd7c3cc9b4d16.png)
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【推荐2】两个边长为4的正三角形
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