如图,棱长为2的正方体ABCD-A1B1C1D1中,E、F分别是DD1、DB的中点,求证:
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/6/10c4b1e5-4c3f-4742-8a5f-7681a3abca51.png?resizew=155)
(1)EF∥平面ABC1D1;
(2)EF⊥B1C.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/6/10c4b1e5-4c3f-4742-8a5f-7681a3abca51.png?resizew=155)
(1)EF∥平面ABC1D1;
(2)EF⊥B1C.
2017高二·新疆·学业考试 查看更多[2]
更新时间:2017-12-26 21:14:45
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解答题-问答题
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适中
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【推荐1】如图,四棱锥
中,平面SAD
平面SAB,BC
SA,
,
,
.
![](https://img.xkw.com/dksih/QBM/2018/6/4/1959869297360896/1959889672871936/STEM/1f767fd95a9e40e99823fbb0c6cb625a.png?resizew=235)
(1)证明:在线段
上是否存在点
,使得
平面
;
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a58ece8dc5f29476a20d1de282116ace.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc1bed9e7cd7aa41d0cb0f9fc1ec5eaf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d78aafccd397e9c88a567abf4993d40f.png)
![](https://img.xkw.com/dksih/QBM/2018/6/4/1959869297360896/1959889672871936/STEM/1f767fd95a9e40e99823fbb0c6cb625a.png?resizew=235)
(1)证明:在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a6e2867f32d3f1c3cd36cd3a11a8580.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9b3b18b7f7e08f195bcdf3acfffff3d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ef796b46e68fe77b117ff0483d2370c.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcf861f488b5ff71135081f1524fdd5e.png)
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【推荐2】如图,在四棱锥
中,侧面
是等边三角形,且平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
平面
,
为
的中点,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/7a445dfe-be49-4b5b-bb88-5e1db2a0c29e.png?resizew=165)
(Ⅰ)求证:
平面
;
(Ⅱ)求二面角
的余弦值;
(Ⅲ)直线
上是否存在点
,使得
平面
?若存在,求出
的值;若不存在,说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.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/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce4ab7e657f01bdfa235f8c4d6681d13.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9fb80d023daff3cc28a8458f29e330fd.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/7a445dfe-be49-4b5b-bb88-5e1db2a0c29e.png?resizew=165)
(Ⅰ)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11d27ff0b39832f094ec51e28721d739.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(Ⅱ)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42f4096ff62b4f29932cd8c6eef661a3.png)
(Ⅲ)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9abe6e8d1f4f1e8bdc46ddbae0cd789.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c66d99a6a8415ddad22bbed33b64cfb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f8fb8f67b04f4be9b166c8265f130ca.png)
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解题方法
【推荐1】如图,在三棱柱
中,平面
平面
,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ddfd52a3543a23547e403090636fed4.png)
,
,
为棱
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/11/13df69d8-09d1-4274-9141-36b7ee0e3d02.png?resizew=187)
(1)证明:
;
(2)求点
到平面
的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61cdaadeae37736a1e6dd93fa1fe712f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ddfd52a3543a23547e403090636fed4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be9d8a9d1b2b30b817d9cdefa7d41788.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4285e6b41d7c9f04e6d562dc9f514400.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/11/13df69d8-09d1-4274-9141-36b7ee0e3d02.png?resizew=187)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ea9a1c949c2bb591c1db240d7874b089.png)
(2)求点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/99b16cff607cdc2d69afc70dc778acbb.png)
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解答题-证明题
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适中
(0.65)
解题方法
【推荐2】如图,在四棱台
中,底面四边形
为菱形,
,
平面
.
;
(2)若四棱台
的体积为
,求点
到平面
的距离.
![](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/7c9d39d37f06906146ae556607006c23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a382ccd078374f1efebb26a43599e596.png)
(2)若四棱台
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fa0d73f30a242947aaf7da525926266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c52091eb745de866044477641a7c55f.png)
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【推荐3】如图,
和
所在平面垂直,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/5a5a0001-fd13-45f4-9ebe-2cba273b62ad.png?resizew=158)
(1)求证:
;
(2)若
,求平面
和平面
的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0005e1ef60f6ddc5f9a83e3de1ef3b2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7b8ea5270ed446a1f73b32517f26e6d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/23/5a5a0001-fd13-45f4-9ebe-2cba273b62ad.png?resizew=158)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b5f215a42c4b7078d8d65923eb9980e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd15ead753cf2927f51d07c7727c6cd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
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