在长方体
中,点E、F分别
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/12/545c0705-6f61-4f0d-8c3d-d679f2ed2d65.png?resizew=175)
(1)求证:
平面
;
(2)若规定两个平面所成的角是这两个平面所组成的二面角中的锐角(或直角),则在空间中有定理:若两条直线分别垂直于两个平面,则这两条直线所成的角与这两个平面所成的角相等.试根据上述定理,在
时,求平面
与平面
所成的角的大小.(用反三角函数值表示)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad907394843e0d4951df908aa4817175.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93df7ae545875597289d00fbb78f16ab.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/12/545c0705-6f61-4f0d-8c3d-d679f2ed2d65.png?resizew=175)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d26d8a9d64ad3c8cba28840b41ed7837.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
(2)若规定两个平面所成的角是这两个平面所组成的二面角中的锐角(或直角),则在空间中有定理:若两条直线分别垂直于两个平面,则这两条直线所成的角与这两个平面所成的角相等.试根据上述定理,在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3a32aa0247b4099d3c3a19d0bd03d1d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b03428a8f91a5674cb8f54766c165f7e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab6bf42c7db96104456424e4d1be6c48.png)
更新时间:2022-11-09 14:06:23
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在四棱锥
中,
底面
,且底面
为直角梯形,
,
,
,
,
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/7/3e7a5f57-3b4b-4c09-b085-2763f7093df5.png?resizew=180)
(1)求证:BE//平面PAD
(2)求证:
平面PCD
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97e45b6f8cf0260912f587c04f9f2442.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ead32f6e1869038b83dd9dffb0912515.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/833cfda415649b832cc136caed392753.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/7/3e7a5f57-3b4b-4c09-b085-2763f7093df5.png?resizew=180)
(1)求证:BE//平面PAD
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
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【推荐2】如图所示,在棱长为2的正方体ABCD﹣A1B1C1D1中,E、F分别为DD1、DB的中点.
![](https://img.xkw.com/dksih/QBM/2020/1/4/2369701273042944/2370058151641088/STEM/c3a893a5077a4ed9809bd6e7d3bfe05c.png?resizew=193)
(1)求证:EF∥平面ABC1D1;
(2)求三棱锥E﹣FCB1的体积.
![](https://img.xkw.com/dksih/QBM/2020/1/4/2369701273042944/2370058151641088/STEM/c3a893a5077a4ed9809bd6e7d3bfe05c.png?resizew=193)
(1)求证:EF∥平面ABC1D1;
(2)求三棱锥E﹣FCB1的体积.
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解答题-证明题
|
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【推荐3】已知三棱柱ABC﹣A1B1C1的所有棱长都相等,平面BB1C1C⊥平面ABC,BC1=C1C.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/d8939072-5dc4-4c14-8160-2ca3c4e273fb.png?resizew=193)
(1)求证:A1B⊥平面AB1C1;
(2)求二面角A1﹣AC1﹣B1的余弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/26/d8939072-5dc4-4c14-8160-2ca3c4e273fb.png?resizew=193)
(1)求证:A1B⊥平面AB1C1;
(2)求二面角A1﹣AC1﹣B1的余弦值.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐1】如图,在四棱锥
中,底面
为平行四边形,
,
,
,
是线段
的中点,点
在平面
上的射影为线段
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/7/c1a31c43-357a-4ead-af84-5af090521b93.png?resizew=304)
(1)证明:
平面
;
(2)若直线
与平面
所成角为
,求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5164a3cc47e266446d49127e2ef10c37.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0402dd5ae3db10281f9f1e11738bcb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7cbfaec1d9dcaaf159b060163436113.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/7/c1a31c43-357a-4ead-af84-5af090521b93.png?resizew=304)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/31c34b18525831f3eda7bb90be0199b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f239fbcc58fc15535db4b5084c4f7253.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c67d01e61dc0042e67b5e8ec8e727c22.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37ad7f1d38fd15f39ee4eddc536b90ed.png)
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【推荐2】如图,D为圆锥DO的顶点,O为圆锥底面的圆心,AB为直径,C为底面圆周上一点,四边形OAED为正方形,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/8/9a159a10-63e7-487f-a275-232653031688.png?resizew=152)
(1)若点F在BC上,且
//面ACE,请确定点F的位置并说明理由;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e20c1b7f55cd8e68a7c3aa58bc944c5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/8/9a159a10-63e7-487f-a275-232653031688.png?resizew=152)
(1)若点F在BC上,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d004d2d115b477ade6af7ddb93db0df8.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11c3762eb09409441a1d1d7c0ccbbe60.png)
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