如图,已知正方体
的上底面内有一点
,点
为线段
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/15/acc4fb82-f5ef-4449-b4f4-46e21dee4b20.png?resizew=176)
(1)经过点
在上底面画一条直线
与
垂直,并说明画出这条线的理由;
(2)若
,求
与平面
所成角的正切值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/15/acc4fb82-f5ef-4449-b4f4-46e21dee4b20.png?resizew=176)
(1)经过点
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bde6d6ab9706c59659c1f16f415825d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eedae8d316c76e3d0b451256de03fb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7865126ef23077f3ed6832899a600732.png)
更新时间:2021-11-08 12:45:37
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图,在几何体
中,底面
是边长为2的正方形,
平面
,
,且
.
![](https://img.xkw.com/dksih/QBM/2020/12/17/2616174184923136/2618454743359488/STEM/90cfa18668ea43a9b7a11d6c58538d1e.png?resizew=186)
(1)求证:平面
平面
;
(2)求证:
;
(3)求钝二面角
的余弦值.
![](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/b8d2d217e9bcd059908f117dfc4d4259.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07d2f152a8da561c9eeb6ba2ef091dc2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd0e59437b5fa6ce66fb2f405dea8f18.png)
![](https://img.xkw.com/dksih/QBM/2020/12/17/2616174184923136/2618454743359488/STEM/90cfa18668ea43a9b7a11d6c58538d1e.png?resizew=186)
(1)求证:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e83e602c2b4540c6c7454f5f0948544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9a32bd7a1b78b5a0ec562c4025aea8c.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fdf23e73ae2a15c04bbed3981cb8e511.png)
(3)求钝二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7e0a3b7d47511f83a3d6fd52f854da04.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,在三棱台ABC-DEF中,AB=BC=AC=2,AD=DF=FC=1,N为DF的中点,二面角D-AC-B的大小为
.
![](https://img.xkw.com/dksih/QBM/2017/2/16/1625399184465920/1625951221760000/STEM/825a3650-bd2f-471b-857a-99da46c42e18.png)
(Ⅰ)证明:
;
(Ⅱ)求直线AD与平面BEFC所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9f785147690f83dcee0a0bc6c327e75a.png)
![](https://img.xkw.com/dksih/QBM/2017/2/16/1625399184465920/1625951221760000/STEM/825a3650-bd2f-471b-857a-99da46c42e18.png)
(Ⅰ)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/adf21399dcf3682bf5d3f9cbd5eed86c.png)
(Ⅱ)求直线AD与平面BEFC所成角的正弦值.
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐3】如图,长方体
的底面
是正方形,点
在棱
上,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/10/e3c6fce1-87c1-4770-91d4-f882626666bc.png?resizew=130)
(1)证明:
平面
;
(2)若
,求二面角
的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2777840758e70e7dbbc18cef8f3d6d2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c810d9d154dbbc0cef6ab8ffcd488045.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/12/10/e3c6fce1-87c1-4770-91d4-f882626666bc.png?resizew=130)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/662698361c6b3ddaf0c28a3c87be53e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/02c4f474f2c144be8703517ef72b98a7.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a4b1fb8aa4fc5533e4418d678c7e55a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e5ba7fc3eecf008fb7aaa79c405b3326.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】如图,在三棱锥
中,
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/15/d998eb7a-11df-4d13-b0df-2154f602b580.png?resizew=148)
(1)证明:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63397cda22cb1fad59cf966dfb588643.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/680bd341c5bc48c24b0d520f66de6512.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/2/15/d998eb7a-11df-4d13-b0df-2154f602b580.png?resizew=148)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ffc6952e988d04f22f0fb2f7f0ab7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/63a253c7fdf589ee3dece13d5b5b5732.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abd284f76d9f5769bc189508ce2572b.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】在正四棱锥P﹣ABCD中,AB=2,
,E,F分别是AB,AD的中点,过直线EF的平面α分别与侧棱PB,PD交于点M,N.
![](https://img.xkw.com/dksih/QBM/2022/1/9/2875931660148736/2938141149700096/STEM/7664161fa79948a7936416232ec88b0a.png?resizew=170)
(1)求证:MN∥BD;
(2)若EF=2MN,求直线PA与平面α所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c85aeab3aeaf4367b711da8cde2e8bd.png)
![](https://img.xkw.com/dksih/QBM/2022/1/9/2875931660148736/2938141149700096/STEM/7664161fa79948a7936416232ec88b0a.png?resizew=170)
(1)求证:MN∥BD;
(2)若EF=2MN,求直线PA与平面α所成角的正弦值.
您最近一年使用:0次