解题方法
1 . 已知:如图,四棱锥
,
平面
,四边形
是平行四边形,
为
中点,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/2/296b77e3-04a0-4935-9c6b-08257295f362.png?resizew=161)
(1)求证:
平面
;
(2)求证:
.
![](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/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1cbab4a3f9636fe3eeee75ba79d08a52.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2024/1/2/296b77e3-04a0-4935-9c6b-08257295f362.png?resizew=161)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f8c2b786c64e6a9ed2ec5670cde74f86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/34be4e71cabf458f17a6cd7f24bc70af.png)
(2)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4999d4fbcbe15f78c29d518f25d317c2.png)
您最近一年使用:0次
解题方法
2 . 如图,在三棱锥中P-ABC,PA
底面ABC,AB
AC,E、F分别是BC、PC的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/12/1096d365-f77d-482f-9218-a22873362c03.png?resizew=158)
(1)证明:
平面
;
(2)证明:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/1/12/1096d365-f77d-482f-9218-a22873362c03.png?resizew=158)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/06222ee533c2484ab25321a6abbf98cb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1e582d73b96ba649378379c3074d506d.png)
(2)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/58cc90fee532e50d319081d571410421.png)
您最近一年使用:0次