在正三棱柱
中,点
是
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/12/90ac46e4-a6d2-4335-bd1e-e9a7a90e085d.png?resizew=155)
(1)求证:
//面
;
(2)设
是棱
上的点,且满足
.求证:面
面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/12/90ac46e4-a6d2-4335-bd1e-e9a7a90e085d.png?resizew=155)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5888bec948373f3854258ad80171073d.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5ed990271713e2d0ee431ce152f0b6d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0fe22d526d1da4d61436c59e7517328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3653ada76ba0c8afe9d57c8e7832c6ed.png)
更新时间:2018-02-28 20:49:30
|
相似题推荐
解答题-问答题
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适中
(0.65)
名校
解题方法
【推荐1】在如图所示的五面体中,四边形
为直角梯形,
,平面![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
平面
,
,
是边长为2的正三角形.
(1)证明:
平面
;
(2)证明:
平面
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef9376572f4c4cb92bdc69936ad0c0f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.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/254c19346da6c865e37c5e72366fd89a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a25c28359f8d8da9eaf4672a6cf8ae4f.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4734735213b599a9915e1ed91a5d8ce4.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/9/26/bfa419eb-c811-47a7-ad5a-e798ac1555be.png?resizew=267)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图,在四棱锥
中,底面ABCD是正方形,AC、BD相交于点O,侧棱
底面ABCD,
,E是PC的中点,过E作
交PB于点F,连接DF,BE.
![](https://img.xkw.com/dksih/QBM/2022/2/12/2915036572844032/2927533208895488/STEM/c8729cae54d84c78b126cae421094989.png?resizew=220)
(1)求证:
平面BDE;
(2)求二面角
的余弦值;
(3)取PA中点G,判断直线DG与平面DEF的位置关系.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/43d4c42112e0a22f240ce2ae432e5b4d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9a4a6a1e70241d600bc6c104313eac61.png)
![](https://img.xkw.com/dksih/QBM/2022/2/12/2915036572844032/2927533208895488/STEM/c8729cae54d84c78b126cae421094989.png?resizew=220)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1666b45ed176d648dd1764f4a2dbd73.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6dd02f171d6ae36135cd30987376e3b7.png)
(3)取PA中点G,判断直线DG与平面DEF的位置关系.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】如图,在四棱锥
中,平面
平面
,
,
,
是等腰直角三角形,
是顶角.
(1)求证:平面
平面
;
(2)若
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93edc7bb513f40a89173121c8570cd65.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cdb2dd10731b99c0f4f89ee957f8a239.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7fbd6b9f85c086ac95562fe45e8d969.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42fa5dff377ef08e416547def489def0.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/21/4f4b7c96-ea8f-4e71-bf28-2798d62b6cc2.png?resizew=191)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4aa9084b8fe0fe05c4388d1f835587b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7df3cbb0e21389791a038f7a9ce6a327.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a438393ddfc7da1804baf4932442bb35.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
【推荐2】如图所示的多面体中,
是平行四边形,
是矩形,
面
,
,
.
(Ⅰ)求证:平面
平面
;
(Ⅱ)若
,求
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/7f84f169e50dc59d4f7a8e1e36f5c847.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7a38e6c6dfde2b19b6b47f35a439a06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95a207a5457027cb8cd587445da5bc2e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c4e4a162f12d12a082b8d8fdd1aeab9.png)
(Ⅰ)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e1b6711e6dd48be6cf8fa52926924d21.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
(Ⅱ)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5144f280c283f799ae4e51192cdfc38.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46e2da608b66c9aee03e2503388ba4fd.png)
![](https://img.xkw.com/dksih/QBM/2017/5/16/1688394395049984/1688466417229824/STEM/8ae8b093e56c468f9bf07c0af3fb87c2.png?resizew=217)
您最近一年使用:0次