如图1,在
中,
,
,
,且
分别为BC,AD的中点,延长CE交AB于点F.现将△ACD沿AD翻折至△AC'D,使得
,如图2所示.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/19/8b25cad7-4f05-4702-a9c6-93257f85a5df.png?resizew=493)
(1)求证:
;
(2)点G为线段C'D的中点,求直线FG与平面BEC'所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/178a27068cf5517ad64f211af10256ec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2c7f0d0987ee427b7efbbf889b9bf16.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e1f4f255d191786f7d330d278868c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/91e1e4115d78e625e9e0f47cdade3286.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/794cd813dabab72619eb276f93c1769e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/6/19/8b25cad7-4f05-4702-a9c6-93257f85a5df.png?resizew=493)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed96a8bd80187c8ed5fdf272832ca8a4.png)
(2)点G为线段C'D的中点,求直线FG与平面BEC'所成角的正弦值.
更新时间:2022-06-17 18:34:31
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相似题推荐
解答题-证明题
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适中
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名校
【推荐1】如图,等腰直角
中
是直角,平面
平面
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/d4bbe491-ab20-4f3e-9f77-697485e58086.png?resizew=200)
(1)求证
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0faed94a64b2dcfc6801b4fca0f16675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/febc9a89d0d1c97b88c0f4acd32b4e67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c674dc5024374f53920947c4cf4baf11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f3ae2178e6103de9edab9ae2a747dffa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77077621f394478e51a28fe3d57861dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/676cc507aed16f9d2a3c86d9b684b8ae.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/8/d4bbe491-ab20-4f3e-9f77-697485e58086.png?resizew=200)
(1)求证
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfa56215467bb416d3d1e712284b8bff.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6261790c66cc71ee3898afabad0c09f4.png)
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解题方法
【推荐2】如图,
是菱形,对角线
与
的交点为
,四边形
为梯形,
,
.
![](https://img.xkw.com/dksih/QBM/2020/3/2/2410899490029568/2411770269810688/STEM/9eda6307187f43659eecd5f9a5eb4de2.png?resizew=206)
(1)若
,求证:
平面
;
(2)求证:平面
平面
;
(3)若
,求直线
与平面
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f1d70fb53a3bc46be3e6365f5ed26496.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06772d7ccc921f77319c503c23326be2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2bc2365bf5abb74954411eace3fd1abc.png)
![](https://img.xkw.com/dksih/QBM/2020/3/2/2410899490029568/2411770269810688/STEM/9eda6307187f43659eecd5f9a5eb4de2.png?resizew=206)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5721abbe6afab23059a9391a64ec2a3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3a04ea8ebc597fd1f5d6bb8df181a2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0fa3254460ecbacecb3e57c5dce227f4.png)
(2)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0038a080c58ec7e69c1c304ea19c1a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fbebb845acefa1bb9862e72da428118f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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解题方法
【推荐1】如图(1)示,在梯形
中,
,如图(2)沿
将四边形折起,使得平面
与平面
垂直,
为
的中点.
面
;
(2)求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2fa7bbd7831e9ff4f8cffc8889d34f05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ede4b77a794c880341f0956e6eb3456.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c09afc70f448545336304333d5b5658b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08f8b463fcecf0a757f386db56e074d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f332555e65843f32f4c623098c6adc72.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd7e284eac4b90bfb327de768a7beef6.png)
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适中
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【推荐2】如图,在四棱锥
中,
面
,
,
,
,
为线段
上的点,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c858454c801c04de4c11d1ed132f147.png)
![](https://img.xkw.com/dksih/QBM/2022/1/9/2890852507148288/2893642063241216/STEM/1113662d371843f5a09eba99a63f825c.png?resizew=148)
(1)证明:
面
;
(2)求
与面
所成的角的正弦值;
(3)若
满足
面
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d02bd5cfe804460846423e77f72db10f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb4564baf209de77802d46cda82995c5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5cb3f9a5da641be35117fd35ba07a6aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06662eecbf8a7d5581c2ffc70d8096d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c899bcc203776282df000208a87aaba.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bde0ec91820d727ab3126fd7e5eceb02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4d260c4df7b0dc180af6980d21f3371.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c858454c801c04de4c11d1ed132f147.png)
![](https://img.xkw.com/dksih/QBM/2022/1/9/2890852507148288/2893642063241216/STEM/1113662d371843f5a09eba99a63f825c.png?resizew=148)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c306e49fd17d29f0174793cb5e1decbd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27d39f37441ee55dbc8f1a6ca199a66b.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d4d260c4df7b0dc180af6980d21f3371.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae3142b1af4ce67d3e55417b4c0de257.png)
(3)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/895dc3dc3a6606ff487a4c4863e18509.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1d3eeb763e27daae71af50e22bfdb42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9208ade3eba5c14c4d5adfd8e580b7a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ef68ac955e0057a783328b06268eb99.png)
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【推荐3】如图,在正四棱柱
中,点M在棱
上,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/103aa60a-80c2-4e10-a711-507a1fb35a8c.png?resizew=132)
(Ⅰ)证明:
;
(Ⅱ)若M是
的中点,求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83999da529b407b8e86b3d4a60bf9798.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/4/103aa60a-80c2-4e10-a711-507a1fb35a8c.png?resizew=132)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/643f9a475188451031ad51b3a6bf06d3.png)
(Ⅱ)若M是
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5563473602e1b17d582a165b7b7b6b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ddb7c2ca1b6bee86cb24fed02e40da2.png)
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