如图,在正四棱锥
中,
,
,
分别为
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/2da3308e-7da3-498c-a289-4a37e1dcf27f.png?resizew=217)
(1)求正四棱锥
的全面积;
(2)若平面
与棱
交于点
,求平面
与平面
所成锐二面角的大小(用反三角函数值表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03c97a79520fa792cf5eaf209f6c8e49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/7/2da3308e-7da3-498c-a289-4a37e1dcf27f.png?resizew=217)
(1)求正四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f11969bbf853d6a703eac037566f3e5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
18-19高二下·上海青浦·期中 查看更多[3]
更新时间:2019-08-17 01:05:05
|
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解答题-问答题
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【推荐2】同底的两个正三棱锥内接于半径
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【推荐1】如图,已知正三棱柱
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/9fb27553-1772-4c39-8aca-1b866d3b7a0f.png?resizew=132)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/13159d685fa1c334798660a5942e29eb.png)
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名校
【推荐2】如图,在四棱锥
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/4/eab1aff7-d3a6-4d0a-985f-6ec343721f40.png?resizew=184)
(1)求证:
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2418a4e59a3d9a27cda7c51c8c7df441.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb8c91e4c85a9da7f54b2237d870a50d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/4/eab1aff7-d3a6-4d0a-985f-6ec343721f40.png?resizew=184)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d451324445a93eb518abdc2bd9a4733.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2de54921b7079102fd045f63335f05e9.png)
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