名校
1 .
是边长为2的正三角形,P在平面上满足
,将
沿AC翻折,使点P到达
的位置,若平面
平面ABC,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/5/922e2631-442f-4c5e-9e86-28355cba488f.png?resizew=265)
(1)作平面
,使得
,且
,说明作图方法并证明;
(2)点M满足
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da35b5c539d7ac40137eb9f665571f53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/147de24f071e316b68fd2e78e3c84545.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cee6765a83140d745a6de4c85d9b6b50.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d9b0255047b563fb5828ba05ea63049a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1095457a1433e68cc63eebe0d0c218c2.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/5/5/922e2631-442f-4c5e-9e86-28355cba488f.png?resizew=265)
(1)作平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/88edffc97ba3b98d5e8c9e55016fa018.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edcc1653fc8447569107a484816b27a7.png)
(2)点M满足
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9da932bf1051907c0433c169fef04b14.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6d4d818cdb553e6e71cf91dac1089257.png)
您最近一年使用:0次
解题方法
2 . 如图,在四棱锥
中,
平面
,底面ABCD满足
,且![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ffbcd82b98a9ae69aa4ee28bb49a907.png)
,三角形
的面积为![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f08596ab7ad94031331c93db6f9ec549.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/27/82af416a-ba84-48a7-8b69-29ea46d5130f.png?resizew=169)
(1)画出平面PAB和平面PCD的交线,并说明理由,
(2)求平面PAB与平面PCD所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34e0a957a55460c72673c0f2ee90dbb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ffbcd82b98a9ae69aa4ee28bb49a907.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c90282d4a37c9a20620d4bbb0c263cae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cfc9df9c661bd93b3f4f51f91534c4a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f08596ab7ad94031331c93db6f9ec549.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/27/82af416a-ba84-48a7-8b69-29ea46d5130f.png?resizew=169)
(1)画出平面PAB和平面PCD的交线,并说明理由,
(2)求平面PAB与平面PCD所成锐二面角的余弦值.
您最近一年使用:0次