名校
1 . 如图,在三棱柱
中,
平面
,
,
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/1086a6ac-8473-4a59-a0a7-82ab95af2f97.png?resizew=164)
(1)证明:
平面ABC.
(2)求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42d3a82b8e587ee890467835bc4e854c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e168672b47d7e64dc1b404f8882c7dcf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ca036d049f5205cf04cb1b9c5cd03f97.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f656e1d1f68954e5f06de8958f6a9310.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41fd676c41d2d644928f014b0fea4689.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/518a322494bd7624e6eed7fe290a2f9f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/14/1086a6ac-8473-4a59-a0a7-82ab95af2f97.png?resizew=164)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e89195bacd53d43195e70c12b5cfa041.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a824c242050a27d9da3bb3276ea99170.png)
您最近一年使用:0次
2020-07-11更新
|
430次组卷
|
4卷引用:新疆昌吉州2022届高三第二次诊断性测试数学(理)试题
2 . 在四棱锥
中,底面
是边长为
的菱形,
,
.
(I)证明:
平面
;
(II)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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e075468e7fb0bf30229aec01a7205977.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/851cf6b3cb9b2486771a0d69ae47c678.png)
(I)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(II)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b80ee363635d73f601654339028daec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad6a0cee8226e82cc57916e10d533369.png)
![](https://img.xkw.com/dksih/QBM/2018/4/24/1931033716408320/1936081014661120/STEM/c7aad0e8c7524bfb8d83cd6855840c79.png?resizew=162)
您最近一年使用:0次
2017-02-08更新
|
1113次组卷
|
7卷引用:新疆克拉玛依市2022届高三第三次模拟检测数学(理)试题