解题方法
1 . 如图,三棱柱
中,侧面
为菱形,
的中点为
,且
平面
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/2dbc15b5-e5d5-4a4d-b9da-f2f797abb58f.png?resizew=230)
(1)证明:
;
(2)若
,
,
,试画出二面角
的平面角,并求它的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d7f6f93171329d508d491143b9d71f7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ce03b310edce42191f9fa75a1c909ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc6184b191e6da43911e701121517e.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/2dbc15b5-e5d5-4a4d-b9da-f2f797abb58f.png?resizew=230)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8db87b41df9d3c83d2810a4265d768d3.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1c7fd49bb962841b4575805030e19add.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eab3c1c4935d98496b8e1eae01b5ecce.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa7aeb2a8d1437eeb4482c3b6ad9f315.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cea67423ce6963c0972867306169f17a.png)
您最近一年使用:0次
2019-07-06更新
|
1047次组卷
|
2卷引用:2019年广东省广州市海珠区高一下学期期末考试数学试题
2 . 如图,在三棱锥
中,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/20/510b755a-5812-4c7f-98b1-706bc12f7d26.png?resizew=196)
(1)画出二面角
的平面角,并求它的度数;
(2)求三棱锥
的体积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/785ba14914716ccd48f8545543a58807.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/10/20/510b755a-5812-4c7f-98b1-706bc12f7d26.png?resizew=196)
(1)画出二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7fe637f1537666932491637f9b3d3ee.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41e5db1d2fd912f77923e4c120a7dc19.png)
您最近一年使用:0次