直角
的斜边
在平面
内.AC、BC与
所成角分别为30°、45°,CD是斜边AB上的高,求CD与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
更新时间:2023-02-06 08:56:43
|
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】如图所示,正四棱锥P-ABCD中,O为底面正方形的中心,侧棱PA与底面ABCD所成的角的正切值为
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/1e91f10d-9630-4476-82cd-ca448481e07d.png?resizew=196)
(1)若E是PB的中点,求证OE∥平面PCD
(2)求侧面PAD与底面ABCD所成的二面角的大小
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4eb00a19477b29b325a5e334207f6b18.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/16/1e91f10d-9630-4476-82cd-ca448481e07d.png?resizew=196)
(1)若E是PB的中点,求证OE∥平面PCD
(2)求侧面PAD与底面ABCD所成的二面角的大小
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在三棱锥中,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/d108e503-c071-444c-b17d-e50fe70732ad.png?resizew=182)
(1)求证:
;
(2)若直线
与底面
所成角的正弦值为
,求二面角
的平面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/47a9169fcd233a32ceeaa307dc6e4cad.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da359812e70fcbdf4303004fd952698d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/d108e503-c071-444c-b17d-e50fe70732ad.png?resizew=182)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a77e3c1c236141d6118429fade0a9b9d.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03902478df1a55bc99703210bccab910.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1174142f3bba761585b6bc2653009b36.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6c2898853a3396f0878af9eac934416d.png)
您最近一年使用:0次
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,底面
是平行四边形,
平面
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/782b7e4d-5f10-41eb-a296-cd6bc9806427.png?resizew=151)
(1)证明:
平面
;
(2)若
与平面
所成角为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a1b49f64e0065edad868b25e9fcada3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/55e1de129bfc451f4c7160cc50666ad8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8195c0daa9a2a267b29a2c094653fbf3.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/782b7e4d-5f10-41eb-a296-cd6bc9806427.png?resizew=151)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca5dd496ee0c1170ef6dcc48266ee444.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f571a1aac46c6d0cf440c0ec2846bf9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15615de1a6df206dbd081251f676578e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1069d514c3c32aeabd274475ee209ed6.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】如图,多面体
中,四边形
是菱形,
,
相交于
,
,点
在平面
上的射影恰好是线段
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/17/f486c529-bf74-4119-bc16-eca6ea5823fb.png?resizew=212)
(1)求证:
平面
;
(2)若直线
与平面
所成的角为
,求平面
与平面
所成角(锐角)的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2fc1129846f37afdafd751627c450d5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4b4101f15891b9c9fed36fd278e69c41.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/73b3c032441543354c154ee67d744abb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68dfd32a77c3615069ad1e7eb5b226a5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2c3d2cba96f6f03520c0b3f6e4da03e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/8/17/f486c529-bf74-4119-bc16-eca6ea5823fb.png?resizew=212)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4734735213b599a9915e1ed91a5d8ce4.png)
(2)若直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68a83fdd2ba72a2dba0b6b10bb3e06b9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/79a97bb4dcfab4ec7539bc783d563c49.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/134ef0b1a2669a09f05bd4dc2496f706.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
您最近一年使用:0次