如图1,在平面五边形
中,
是等边三角形.现将
沿
折起,记折后的点
为
,连接
,得到四棱锥
,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/23/ffd63930-2bec-4ac1-b862-c1b5aed3206f.png?resizew=308)
(1)证明:
;
(2)若平面
平面
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9142a8490de14a87eda628ffa7e28982.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3acd2679b6ce05d6a67cb67bee919ba6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3b1a5427d8ff23df0f3ec194756c84c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d92a66d30863976e2036fc4cbf93c906.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78c49e04a1cbd79bfe0f8fdb4fd390fe.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/23/ffd63930-2bec-4ac1-b862-c1b5aed3206f.png?resizew=308)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8eceea730492c7927bb34c5d413a7a9.png)
(2)若平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/615ed3b93483bb2f6d86acce159735c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffea72549ea46b2819e827c32307b5b9.png)
更新时间:2024-02-23 11:43:11
|
相似题推荐
解答题-问答题
|
适中
(0.65)
真题
【推荐1】在三棱锥
中,
是边长为
的正三角形,平面
平面
,
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/43384b0e-4b23-414b-8860-3b4e151dcd64.png?resizew=151)
(1)证明:
;
(2)求二面角
的大小:
(3)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8860d9787671b53b1ab68b3d526f5ca.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/78307cd417504554a4e2276fe24d1162.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55ca6072b3a2aac406a2b60bb7e01cde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/15/43384b0e-4b23-414b-8860-3b4e151dcd64.png?resizew=151)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90fa715d27ae43ec1e157226bc9dea54.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8755c1a540992d405d7e4bc3e918d7b.png)
(3)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a81b7c9e813895fc25d32a52e15c5f4.png)
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名校
解题方法
【推荐2】如图,直四棱柱
中,底面
是边长为1的正方形,点
在棱
上.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/0daaa5d5-1d2e-483c-b1b8-d28103505dee.png?resizew=142)
(1)求证:
;
(2)从条件①、条件②、条件③这三个条件中选择两个作为已知,使得
平面
,并给出证明.
条件①:
为
的中点;
条件②:
平面
;
条件③:
.
(3)若
为
的中点,且点
到平面
的距离为1,求
的长度.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](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/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/7/0daaa5d5-1d2e-483c-b1b8-d28103505dee.png?resizew=142)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0af20277067fdd1bf5b03cea567c0a84.png)
(2)从条件①、条件②、条件③这三个条件中选择两个作为已知,使得
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88b90810b206fa24f92d84504169e02e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81bf7a859123936a07193592e089340a.png)
条件①:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
条件②:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7542b49ab149f2be8ba6b48392bef1f4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81bf7a859123936a07193592e089340a.png)
条件③:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a948b9a017c589727827d944ef1224c.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81bf7a859123936a07193592e089340a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
您最近一年使用:0次
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名校
【推荐1】如图,在四棱锥
中,底面ABCD为矩形,
平面ABCD,
,
,点E在线段AB上,且
.
![](https://img.xkw.com/dksih/QBM/2022/1/14/2894545697980416/2895584594976768/STEM/e81b76a723354df689df97bbcfa0ca56.png?resizew=151)
(1)求证:
平面PBD;
(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/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3b610c9b9948d88eda8de0fb8d1cf972.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea8ecef114636eab2c939ebc5b84d77e.png)
![](https://img.xkw.com/dksih/QBM/2022/1/14/2894545697980416/2895584594976768/STEM/e81b76a723354df689df97bbcfa0ca56.png?resizew=151)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44b190c8d3d7d7d0e6e959e8a52eae90.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5ba4ee1fd8cf910368d77571a9289b7.png)
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解答题-证明题
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适中
(0.65)
【推荐2】如图,在四棱锥
中,底面
是菱形,
,
,
,
平面
,
是
的中点,
是
的中点.
(1)求证:
∥平面
;
(2)求证:平面
平面
;
(3)求平面
与平面
所成的锐二面角的大小.
![](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/f945a69cf7e8213e50622125cde652f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcc532cfe64300cb3da9e04a307c957a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](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/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7fbbe7f48676298f2ee0cb1901992eaf.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0ba869e032fb27e1c8e8066c6b0c5c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(3)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://img.xkw.com/dksih/QBM/2012/2/4/1570713482018816/1570713487572992/STEM/450270f311f544cca0f615db6fee0f98.png?resizew=213)
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