如图,在四棱锥
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f1a92aad15f8e45babf2bc84bfb4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
,
为
的中点,连接
.
![](https://img.xkw.com/dksih/QBM/2022/1/21/2899245032554496/2912111437094912/STEM/6125f0f2-cb5e-4362-bb22-3fde17ea0028.png?resizew=197)
(1)求证:
平面
;
(2)求平面
与平面
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f1a92aad15f8e45babf2bc84bfb4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9242c9d6ac1d81f616d900ab3a6ddcc3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d18dca4118ad3f45efdbc92e286d634.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1184ae384a5a0b4e2f50a69f0c884276.png)
![](https://img.xkw.com/dksih/QBM/2022/1/21/2899245032554496/2912111437094912/STEM/6125f0f2-cb5e-4362-bb22-3fde17ea0028.png?resizew=197)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3e126c16032892966489053f44b9048.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
更新时间:2022-02-08 18:48:47
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相似题推荐
解答题-证明题
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解题方法
【推荐1】如图,在棱长都相等的正三棱柱ABC-A1B1C1中,D,E分别为AA1,B1C的中点.
![](https://img.xkw.com/dksih/QBM/2022/2/20/2920728588959744/2935568370106368/STEM/00513f00-cf71-4ba9-a4b0-05667641331c.png?resizew=156)
(1)求证:DE
平面ABC;
(2)求证:B1C⊥平面BDE.
![](https://img.xkw.com/dksih/QBM/2022/2/20/2920728588959744/2935568370106368/STEM/00513f00-cf71-4ba9-a4b0-05667641331c.png?resizew=156)
(1)求证:DE
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
(2)求证:B1C⊥平面BDE.
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【推荐2】如图,在四棱锥
中,底面
为正方形,
,点
在底面
内的投影恰为
中点,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/e5309f11-645d-4e75-8ab9-735cab478e58.png?resizew=205)
(1)若
,求证:
面
;
(2)若平面
与平面
所成的锐二面角为
,求直线
与平面
所成角的正弦值.
![](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/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8361ee004d1e0716806b41a637a09c8a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/17/e5309f11-645d-4e75-8ab9-735cab478e58.png?resizew=205)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1eb1c56398a34848942453685f53bbad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a7442b64b37f685bc3ae88ff450c1a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d88591679796c52024d11c4de641bdb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/892909e49156f7dcc0650fcd65243877.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
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【推荐3】如图,在正方体
中,
分别为棱
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/2/8698ed1d-2800-4cc9-bc85-3db267b69d20.png?resizew=168)
(1)求证:
平面
;
(2)求CB1与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad056c25c0fdcbcc765eb5cbc6093f2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/2/8698ed1d-2800-4cc9-bc85-3db267b69d20.png?resizew=168)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e86eec8526479272d15bb3b171a46de0.png)
(2)求CB1与平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a89b167e964aecdf9836ec6de5a911f.png)
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【推荐1】如图,四边形
为正方形,
,
分别为
,
的中点,以
为折痕把
折起,使点
到达点
的位置,且点
在平面
上的投影点
恰好在
上.
![](https://img.xkw.com/dksih/QBM/2022/4/19/2961427359465472/2963639397244928/STEM/e7da9cae-560e-471c-a787-c2f5af65f140.png?resizew=247)
(1)证明:
.
(2)求二面角
的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15a37ba261860ddad9d11b2e8348a8f3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85719346f464a101d365d42be27450a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73465a1f9aa03481295bf6bd3c6903ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://img.xkw.com/dksih/QBM/2022/4/19/2961427359465472/2963639397244928/STEM/e7da9cae-560e-471c-a787-c2f5af65f140.png?resizew=247)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac536e856feb18e6675a661f8fa44470.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87e7f8fed61cb80e01a9c250b20e15c6.png)
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【推荐2】在三棱柱
中,底面是边长为
的等边三角形ABC,
,点
在底面上的射影是△ABC的中心O.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/4/fa7dde4b-80fa-4655-9caa-1bc9030be92c.png?resizew=180)
(1)求证:平面
⊥平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cef812f839622326a7d7027cc806aaeb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92535536bd3c2761724fd058427f95a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a18722354086c42e62334983fc50eb6a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/4/fa7dde4b-80fa-4655-9caa-1bc9030be92c.png?resizew=180)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a8757caaf61dd37db7a297c6c77b8881.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/32bbdf5dbf9df96742624ada95c36146.png)
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