如下图所示,
是一个四棱锥,已知四边形
是梯形,
平面
,
,
,
,
,点E是棱
上的点,
平面
,点F在棱
上,
.
![](https://img.xkw.com/dksih/QBM/2021/12/31/2884159688376320/2890065184342016/STEM/f682849305184645a2b449b75a083545.png?resizew=263)
(1)直线
与
所成的角的正切值:
(2)若
,证明:
;
(3)问
为多少时,平面
平面
?
![](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/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdb2dd10731b99c0f4f89ee957f8a239.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0799ff7b219b85d6c118e116c9b5fe5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e673ef2d48215ca84a48377f17d6df00.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/137fcdac119eff6ac5990b6d201615df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/564376a88fa74090de9f7694226a6184.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e125d3786e99ea19ff485bbe0d4d6e2c.png)
![](https://img.xkw.com/dksih/QBM/2021/12/31/2884159688376320/2890065184342016/STEM/f682849305184645a2b449b75a083545.png?resizew=263)
(1)直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df44d1ff1227c4de03ca21ac87f3f86a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a9677deecea626aa6e4078f0b532ba68.png)
(3)问
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f6dd051db98c531f9ef18cdfd793f4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
更新时间:2022-01-08 15:15:34
|
相似题推荐
解答题-问答题
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适中
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名校
【推荐1】如图①:在平行四边形
中,
,
,将
沿对角线
折起,使
,连结
,得到如图②所示三棱锥
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/8/ec496132-1a0e-4758-8763-272c55d6b424.png?resizew=396)
(1)证明:
平面
;
(2)若
,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff9c7cbcc38b28d45c8539710e5b260a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c897a54f2e36bc4b52fba74b41c89d2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db5e1441a49e782ff0ef46e776cde06a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28a44710ecd04cc60a221bb1ed7b34fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/891579e7c231584a8e16b8eeff79888e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/8/ec496132-1a0e-4758-8763-272c55d6b424.png?resizew=396)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d78fc7fcb2762de28dcef8aa3aa0e49.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5e2dc196e3e33c4864bb2d8447f62f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d78fc7fcb2762de28dcef8aa3aa0e49.png)
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解题方法
【推荐2】如图,在四棱锥
中,
平面
,底面四边形
是正方形,
,点
为
上的点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/19bfb36c-55fe-476f-8cbb-7ed31051d200.png?resizew=151)
(1)求证:平面
平面
;
(2)求二面角
的正弦值.
![](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/36dc88c2054948a03e74d57b10d3a482.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/1b384315ba84cafb978ef3619c8162b5.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/10/19bfb36c-55fe-476f-8cbb-7ed31051d200.png?resizew=151)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/053932dc8c5eebbc739256cb4de6c71d.png)
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【推荐1】如图所示,在四棱锥P-ABCD中,底面ABCD是边长为a的正方形,侧面
底面ABCD,且
,若E,F分别为PC,BD的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/b473e904-1e8f-471d-9119-293dad237ee3.jpg?resizew=188)
(I)求证:EF//平面PAD;
(II)求三棱锥F-DEC的体积;
(III)在线段CD上是否存在一点G,使得平面
平面PDC?若存在,请说明其位置,并加以证明;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1b7201f9eb7e7c10042c096e0c9f15c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/3/b473e904-1e8f-471d-9119-293dad237ee3.jpg?resizew=188)
(I)求证:EF//平面PAD;
(II)求三棱锥F-DEC的体积;
(III)在线段CD上是否存在一点G,使得平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5394d00a80a5900d7fd7d9961868bd22.png)
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【推荐2】如图,在三棱柱
中,底面ABC为正三角形,
底面ABC,
,点
在线段
上,平面
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/397b85c1-c368-4251-bcbf-148eefbecbe4.png?resizew=227)
(1)请指出点
的位置,并给出证明;
(2)若
,求
与平面ABE夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5845ccc0d735dc14c92a8926d9b1def6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7a724f22477766879d1e103e5a6c0b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcadc521b53fabecc10ed30fe8d96c2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/30/397b85c1-c368-4251-bcbf-148eefbecbe4.png?resizew=227)
(1)请指出点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ced06b71073e1bb777f326f06016ce17.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f1158eaa2e338f564eb18de5bef1d25.png)
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【推荐1】如图所示,已知空间四边形
的每条边和对角线长都等于1,点
分别是
的中点.设
,
,
.求异面直线
和
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b199a99e53d67ff4abf233930961a29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/868a68302dfab497e705816c2b1c9708.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f3adc4ed291596abf3bb93ae7a075d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cc03a3ba496faee748a8d63e5d4fa92.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/381985fdee6a1ac3ad4a73f5f653b84c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77a7e4a6765ce78b05ee97764771e01f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/23/c73f5581-46f0-44e3-9def-b907a8843162.png?resizew=155)
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【推荐2】如图,已知正方形ABCD和矩形ACEF中,AB=
,CE=1,CE⊥平面ABCD.
![](https://img.xkw.com/dksih/QBM/2018/6/29/1977865568436224/1979696419856384/STEM/5e8dc88747d645b08ca14ea89e3f07f6.png?resizew=242)
(1)求异面直线DF与BE所成角的余弦值;
(2)求二面角A-DF-B的大小.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf298f00799cbf34b4db26f5f63af92f.png)
![](https://img.xkw.com/dksih/QBM/2018/6/29/1977865568436224/1979696419856384/STEM/5e8dc88747d645b08ca14ea89e3f07f6.png?resizew=242)
(1)求异面直线DF与BE所成角的余弦值;
(2)求二面角A-DF-B的大小.
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