已知正方体
棱长为2,
分别为
的中点,若线段
上一点
满足
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/e4ca50c1-fd10-4efb-b280-511659fdd6ed.png?resizew=171)
(1)确定
的位置;
(2)求
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/0b199a99e53d67ff4abf233930961a29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/82f947af7650af9b75453d89edcda3f5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e72b2e1ff83e95df048745322982451.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d6650610f3f21ac459da8a86d4890ee.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/20/e4ca50c1-fd10-4efb-b280-511659fdd6ed.png?resizew=171)
(1)确定
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac047e91852b91af639feec23a9598b2.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e516121599c9fcc528121c00afcf52fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db34bba418fe95b477069b2652a52975.png)
更新时间:2019-12-02 17:14:55
|
相似题推荐
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,直四棱柱
的底面为正方形,P,O分别是上、下底面的中心,E是AB的中点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/5/e25ce1e5-e32d-4d0b-9f0a-bf91490172a8.png?resizew=220)
(1)求证:
平面
;
(2)当
时,求直线
与平面
所成角的正弦值;
(3)当k取何值时,O在平面
内的射影恰好为
的重心.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5254f01a199d19ac9a1371d87249336e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/3/5/e25ce1e5-e32d-4d0b-9f0a-bf91490172a8.png?resizew=220)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3506f78513da0b4a5c522246e71c76e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9cc66cd5ccd5a579a42c6a241c62d764.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
(3)当k取何值时,O在平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c025ee3317be1099b7bf03a11e37ed4.png)
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2】已知直三棱柱
中,侧面
为正方形,
,E,F分别为AC和
的中点,D为棱
上的点,设
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/1d60f797-e9a6-49ba-8a19-0d5a000a5c8d.png?resizew=156)
(1)证明:
;
(2)当
为何值时,平面
与平面
的夹角的余弦值最大.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e9edc50f7febbc2d5d8dcdc23a3630a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f121eabff3c62c1a196d9ca5f6f83f0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc92d84d188c66b435664a7e7b5a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/271dadac52f2bb8f5f3efe9c90174d0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0023280949eda97787964f0a9d41ed2e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/23/1d60f797-e9a6-49ba-8a19-0d5a000a5c8d.png?resizew=156)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6a7a3dc3f3a02f4400e22dec2f2fee23.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
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】将
沿它的中位线DE折起,使顶点C到达点P的位置,使得
,得到如图所示的四棱锥
,且
,
,F为PB的中点.
(1)证明:平面
平面
;
(2)求直线AP与平面ADF的夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef227e3c17e425d6809b50489f83f50b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c1fd0b59a8d94c6e0b7a89c43f048247.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7277341c0e7f681a37d41c9df4bf7153.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/822ba132ca9dd0d4a050659aef3c9b26.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/5/fb85241b-b882-4a62-8ecb-090c10a84948.png?resizew=158)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90d96357a07048ba79b8c84097d359d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad3a079cfdcca9acdacecbf08f9f78cc.png)
(2)求直线AP与平面ADF的夹角的余弦值.
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2】如图,在正三棱柱(底面为正三角形的直棱柱)
中,已知
,点
为
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/a1c21658-a343-4a5c-98ce-06f7a3f15dd1.png?resizew=141)
(1)求证:平面
平面
;
(2)求直线
与平面
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/92105835f8075cb75dff244e908370b5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/23/a1c21658-a343-4a5c-98ce-06f7a3f15dd1.png?resizew=141)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/46a7d3367f58b3d9d4daeb078cb423b1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f96c673a2381f118ea2d3efc0bca1f3.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d88bf46ad08f9677c37eed1d0369329.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7cbc96c20ebba91031a1c54037fe651c.png)
您最近一年使用:0次