已知如图,菱形
的边长为2,对角线
,现将
沿着对角线
翻折至点
.
![](https://img.xkw.com/dksih/QBM/2020/7/7/2500833578991616/2503126957441024/STEM/67e41d7989ba4411bc8ba28b5831f049.png?resizew=310)
(1)求证:
;
(2)若
,且点E为线段
的中点,求
与平面
夹角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8e1f4f255d191786f7d330d278868c2d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3953cec61ac602ce5eb59b7912352179.png)
![](https://img.xkw.com/dksih/QBM/2020/7/7/2500833578991616/2503126957441024/STEM/67e41d7989ba4411bc8ba28b5831f049.png?resizew=310)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5246843f1a889aa46674bfe3a404c184.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60003c880778ebf5345fa949e27d5642.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab41cce6eb2d3058a644314865d16548.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47ce36044e81456a40b5f63749c814e5.png)
更新时间:2020-07-10 22:47:44
|
相似题推荐
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,在直三棱柱
中,D,E,F分别为AC,AB,
的中点,且
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/c0ad96ae-b565-49d0-ab87-cf35c7ac3064.png?resizew=140)
(1)证明:
平面
;
(2)求点A到平面DEF的距离.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/56f7ba05c54b3de1f4378f7c8eb58328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bb5b12692517a39c320f99a479eb055.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d2c15801fee2405573677484f5dcfa4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b57fdd2a3642716fcf5100011eb3ec88.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/29/c0ad96ae-b565-49d0-ab87-cf35c7ac3064.png?resizew=140)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d9a8181f7a7fe7f3fac872ce9534f15.png)
(2)求点A到平面DEF的距离.
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解答题-证明题
|
适中
(0.65)
【推荐2】如图,在直角梯形ABCD中,
,AB⊥AD,且
,现以AD为一边向形外作正方形ADEF,然后沿边AD将正方形ADEF翻折,使平面ADEF与平面ABCD垂直,M为ED的中点,如图2.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/791c573a-dd84-4689-9441-7fc458baee6e.png?resizew=332)
(1)求证:
平面BEC;
(2)求证:BC⊥平面BDE;
(3)求直线BC与平面ADEF所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f79863ffcfa63117ca6741b20a48e69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f409dc2c4f3b7c054d954fd5a613698.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/9/791c573a-dd84-4689-9441-7fc458baee6e.png?resizew=332)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ac480d8d9d7821b62a603cf5cfda236.png)
(2)求证:BC⊥平面BDE;
(3)求直线BC与平面ADEF所成角的正弦值.
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解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,在四棱锥
中,
,
,
,点P在以AB为直径的半圆上(不包括端点),平面
平面ABCD,E,F分别是BC,AP的中点.
![](https://img.xkw.com/dksih/QBM/2023/1/14/3152504890851328/3153960178040832/STEM/27013859caa042dba47c0d9d5f678dd4.png?resizew=189)
(1)证明:
平面PCD;
(2)当
时,求直线EF与平面PBC所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0fff774b4b0087a6f304ce930d359be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4a0e5697eca3f5205cb7b343648240bf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/555e29e445c95ddb514840f63fbb1d12.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baf42acb8d1875acf1775e30ae2e3d62.png)
![](https://img.xkw.com/dksih/QBM/2023/1/14/3152504890851328/3153960178040832/STEM/27013859caa042dba47c0d9d5f678dd4.png?resizew=189)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/073a88b42836fb88433679932b48ad03.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a95d82d0c6d849d7b55491e472b88ab.png)
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【推荐2】如图,是等腰直角三角形,
,
,
分别为
的中点,沿
将
折起,得到如图所示的四棱锥
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f9157fce2a8339d281178c7c0bccbe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d99ecfa8dabb812e134aec7f611189a.png)
(2)当四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48a1c8ccbabbbbb7bfcaa060807ac379.png)
(i) 写出最大体积;
(ii) 求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ae72f1da4f5d540dc1e6f42ea08f952e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55bb03ab214cf6a07f4ecc48426d30da.png)
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