在
中,
,以
为边在平面
内作如图所示的等边
,E为
边上一点,且
,F为线段
上的点,现沿
将
折起,使A点到达位置
,且
点在平面
内的射影恰为E点.
![](https://img.xkw.com/dksih/QBM/2021/1/30/2647331805560832/2648164685848576/STEM/481b008e1eae4495ae32b64f823c1e09.png?resizew=416)
(1)求证:
;
(2)求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f8f88798ec42a58dccd212586382b23.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5b8b98b2f83279a49e94d9f48c5e6f2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/661ff55b5ebbadfb600989af3cfce2fd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/de01ca42a21f0cb44b2c914e092a0d85.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/004104bafb5f30338123d4ea2b7fedde.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
![](https://img.xkw.com/dksih/QBM/2021/1/30/2647331805560832/2648164685848576/STEM/481b008e1eae4495ae32b64f823c1e09.png?resizew=416)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edfb5dc0eff7117a3f4c60b1ae92ca43.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88bf2517bc0b55ab99049feb741eef85.png)
20-21高二上·浙江宁波·期末 查看更多[3]
更新时间:2021-01-31 20:47:45
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相似题推荐
解答题-问答题
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适中
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【推荐1】如图,在四棱锥P−ABCD中,底面ABCD为平行四边形,侧面PAD⊥底面ABCD,PA=PD,点E为BC的中点,△AEB为等边三角形.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/19/8a32fa69-bf39-4c25-93ac-2f637027d084.png?resizew=197)
(1)证明:PB⊥AE;
(2)点F在线段PD上且DF=2FP,若二面角F−AC−D的大小为45°,求直线AE与平面ACF所成角的正弦值.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/19/8a32fa69-bf39-4c25-93ac-2f637027d084.png?resizew=197)
(1)证明:PB⊥AE;
(2)点F在线段PD上且DF=2FP,若二面角F−AC−D的大小为45°,求直线AE与平面ACF所成角的正弦值.
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【推荐2】如图,多面体
中,四边形
为矩形,二面角
的大小为
,
,
,
,
.
(1)求证:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9165d9bfbb0f0d19eb482c2a4c1b29b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41952e78731dc57a028a93672c9ec29c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1e5fa72f2878b476bc57f0df12d6555.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5519c1efed9b34725446c2ee488ab3c1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddbb52f9b226b1db3f6f9f055948bd38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09d27bd71d79cb19eb554175e4ef0867.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/40560ea08d6cd8c1d4d9661ee6faaa3b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/16/e74b5473-27e4-4de6-a6b7-67020fa5e0c3.png?resizew=243)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c8ccd4181f956f6e0140bf0ab8f0716.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b32c05247f6998d7a70d31d13be4148c.png)
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【推荐3】如图,在梯形
中,
,以
为折痕将
折起,使点A到达点
的位置,连接
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/28/05e9c83b-f5c6-45a5-9339-eb04f1bf2dd6.png?resizew=359)
(1)若点E在线段
上,使得
,试确定E的位置,并说明理由;
(2)当
时,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52e16786a1ec55a9a9986b0acc1b8585.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7c314398e26ffc7164b82946eeb4273.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eb97aff0960e2640314888a38e7169c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/28/05e9c83b-f5c6-45a5-9339-eb04f1bf2dd6.png?resizew=359)
(1)若点E在线段
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60060c25f8d9538d971973a5ea49048a.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a871c2279db5c63f5548dcff7e20fbd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/719103f93166bab4828257608e641a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca67a5b8f69507c8b80379e86f90a8ce.png)
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【推荐1】如图所示,在七面体
中,四边形
是边长为
的正方形,
平面
,
平面
,且
,
,
与
交于
点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/e70b79ec-64b1-4da4-8631-bf3be3be3525.png?resizew=148)
(1)在棱
上找一点
,使
平面
,并给出证明;
(2)求平面
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c162736b719327a2acd7c4d313e1d93.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bb92a5e7dc942c44d0f6d7f3906ff804.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c611de332ba0c529d633a6cfe5240d3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db65c1d07d95810704181b60bb25e3d0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9b5231649034fe4700f27f36c1a6147c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e5c62f22d7afc5627fcb86599faa8e1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e0a8cfb3747c454e0698e12857ffae8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/25/e70b79ec-64b1-4da4-8631-bf3be3be3525.png?resizew=148)
(1)在棱
![](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/fd812d8cbe97b02449223ae94cc8511a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4e8a20c1fc8a5620db5db3a74eb01201.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81166ad08996b441effff746335fdb87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/588690c4a218025937357ffab8d63c7a.png)
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解题方法
【推荐2】四棱锥
中,
平面
,底面
是菱形,
,
,点
是棱
上一点.
![](https://img.xkw.com/dksih/QBM/2021/7/6/2758529858240512/2766958380507136/STEM/a0eda382-3121-4993-b24c-70081944ff14.png?resizew=276)
(1)求证:平面
平面
;
(2)当
为
中点时,求二面角
的余弦值;
(3)若直线
与平面
所成的角为
时,求
.
![](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/ea4f5eec0addba78f2e0cdfb7ecc59a6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36b72c6d2ae4924f930c437542b3356a.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/2021/7/6/2758529858240512/2766958380507136/STEM/a0eda382-3121-4993-b24c-70081944ff14.png?resizew=276)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d077f6da8b2c00b152d4679aa2ed7f7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)当
![](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/445b51117626fbd3373e32acc514c64b.png)
(3)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/85c4bdfb0db1e31e8459df1d15f9ab55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
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