如图,在四棱柱
中,底面
是等腰梯形,
是线段
的中点.
![](https://img.xkw.com/dksih/QBM/2022/5/28/2988956284313600/2989662186029056/STEM/336c1986-40b2-4343-9071-6e64f3acc0da.png?resizew=195)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ef601ca1f9c4c031adab4ffed297f0.png)
平面
:
(2)若
,且
,记
为
的重心,求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df45b94c057452f695ffe15c9813270d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://img.xkw.com/dksih/QBM/2022/5/28/2988956284313600/2989662186029056/STEM/336c1986-40b2-4343-9071-6e64f3acc0da.png?resizew=195)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/19ef601ca1f9c4c031adab4ffed297f0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895d6f710d5f67e1d4c7408d50d77281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6442b700594a66d981029ddd48a1cac.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d30639500cf0a244552927ed9be855c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3315b0f3f920d7ec25c9407343e85399.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d32129d9513b5fb7ae2bdc1b6fae61d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/33af2b3543f6aa6eba26dcc58da17bcb.png)
更新时间:2022-05-29 08:26:11
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在四棱锥P-ABCD中,E是棱PC上一点,且2
=
+
,底面ABCD是正方形,平面ABE与棱PD交于点F,平面PCD与平面PAB交于直线l.求证:l∥EF.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8287a29a7d8825e8721ff60277fa3d19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/237889e5a8ce0918e95fc9c91b65bfac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aaa852f7318d1eb2cc3dd877768d8ad2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/5/00f21eed-6690-4682-8178-cb1146b4665b.png?resizew=199)
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解答题-证明题
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解题方法
【推荐2】如图所示在长方体
中,
,
,
,
,
分别是
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/826898a2-7244-4450-83f9-bd1aab1da420.png?resizew=198)
(1)求证:
平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/596d5398203e5dfda7d07ce501b6e6a4.png)
(2)求C到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84f23a20779cbf15d4300ffc69f27f14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5613c5d5fa1332cebd0a5d18d9f0ea16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e44374cc9f8e36b164e5fc99ee227dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a6af86610a29de883bbb8f69b5a6504.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c7d98f1afd9616821ac5c82ab185f6a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/24/826898a2-7244-4450-83f9-bd1aab1da420.png?resizew=198)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7592c4f01c8e06c7ee90df5b9413a9f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/596d5398203e5dfda7d07ce501b6e6a4.png)
(2)求C到平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12f2978d6d7c2b7e658e0149dabe5c14.png)
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解答题-证明题
|
适中
(0.65)
解题方法
【推荐3】如图,在直角梯形
中,
,
,
,
平面
,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/21/6ca83297-0031-41ec-9b5f-18705f815247.png?resizew=142)
(1)求证:
,
,
,
都是直角三角形;
(2)在
上取点
,
交平面
于
,求证:四边形
为直角梯形.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c709ccf950ed4d37ad9e9234dd2446b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31444b36371dcd6fe036a160ecc8127f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4217f4375caaeef4d4221143d5f6bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8c07185992d8fffdb9b775bc3771065c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/21/6ca83297-0031-41ec-9b5f-18705f815247.png?resizew=142)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5830322dd2824ed012a68f1a2bd9c742.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72e49817548cb45b3d1e58570644c6fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d922961b9ff35f5489182304f9f4212a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e59616322b8f735bb29bc2dd3c4d3a1f.png)
(2)在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/defa5b53043ae802bb1af7d14374406d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c2bc5e50b8dfa02601c70822252854a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3653ada76ba0c8afe9d57c8e7832c6ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/54a5d7d3b6b63fe5c24c3907b7a8eaa3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e53abbd672b82a02c4975f99fbbd2c37.png)
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解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,在四棱锥P-ABCD中,PA⊥底面ABCD,BC
AD,AB⊥BC,PA=AB=
AD=2BC=2,M是PD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/58473167-b899-4173-bb11-b41d49f50246.png?resizew=161)
(1)求证:CM
平面PAB;
(2)求三棱锥P-ACM的体积;
(3)求二面角M-AC-D的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58db0e1f4ae4ed44ae8ad87a09b27a98.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/27/58473167-b899-4173-bb11-b41d49f50246.png?resizew=161)
(1)求证:CM
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fb31ef428bd9de9bc875b343feded3c7.png)
(2)求三棱锥P-ACM的体积;
(3)求二面角M-AC-D的余弦值.
您最近一年使用:0次
解答题
|
适中
(0.65)
名校
【推荐2】已知四边形
为等腰梯形,
,
沿对角线将
旋转,使得点
至点
的位置,此时满足
.
(1)判断
的形状,并证明;
(2)求二面角
的平面角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84ea583e7b2d2a4e51679d2e06724b58.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5bb961bd7db3adb76af2d4cedb611bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c65334978b0519b379910dfc4acf8344.png)
(1)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9017cfed5393f9b21602107ed164c733.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b33b7213d99a817bff19bcf740a0697c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/6/e4e77187-27e1-4e3f-ba88-49e0fc6d5a95.png?resizew=370)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】如图,四边形
为正方形,
平面
,
为等腰三角形,
,
.
![](https://img.xkw.com/dksih/QBM/2021/5/12/2719393821089792/2722310467592192/STEM/96c8d89e-2a8b-4886-9f83-a4a82002ca72.png?resizew=219)
(Ⅰ)求证:
平面
;
(Ⅱ)求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.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/2205cffebf8c4d5f81d15ed7b85c8936.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3755b2bcf7516eedb26a27ad73657216.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/105417b995ed5a83a8e59538b5173795.png)
![](https://img.xkw.com/dksih/QBM/2021/5/12/2719393821089792/2722310467592192/STEM/96c8d89e-2a8b-4886-9f83-a4a82002ca72.png?resizew=219)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b5f1897a7e856b42f8cee0f286ad913d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d5c66edca50eace2fad71ef59d73c662.png)
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