如图,在正六面体
中,
,
,
,
,过E,F,G的平面m截正六面体
得一平面多边形n.
![](https://img.xkw.com/dksih/QBM/2021/1/9/2632461061021696/2633736375115776/STEM/d85ae0abb15b408e98fff70f43c861a6.png?resizew=159)
(Ⅰ)求多边形n的周长和面积;
(Ⅱ)求m与平面
所成的二面角的平面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78b65065ec3a0cb4b050989165c003d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60634341a9603e24b2bbc6960abe3d31.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60572975f9ac06ffc8d98ef94de49eb0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60d1cbd48054865bf9b26712853e10c8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://img.xkw.com/dksih/QBM/2021/1/9/2632461061021696/2633736375115776/STEM/d85ae0abb15b408e98fff70f43c861a6.png?resizew=159)
(Ⅰ)求多边形n的周长和面积;
(Ⅱ)求m与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
更新时间:2021-01-11 11:33:17
|
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解答题-作图题
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【推荐1】如图,在正方体
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解答题-作图题
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名校
【推荐2】在长方体
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(2)如图2,已知
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将长方体分成两部分.现同时将两个球分别放入这两部分几何体内,则在平面
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(1)若点
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(2)试问点
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a5df4b7ea378e4463e0d7846a9f783e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
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解答题-问答题
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较难
(0.4)
名校
解题方法
【推荐2】如图,
平面
,
,点M为BQ的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/16/88b42448-72d2-4f6b-8dbb-4e4af98c0ed5.png?resizew=183)
(1)求二面角
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与平面
所成的角为
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24aca9af25c07f031e00ad681d3d9978.png)
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