名校
解题方法
1 . 如图,在四棱锥
中,底面
为平行四边形,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
平面
为
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/235226e4-5388-4c9b-bb30-9a28d68e43b6.png?resizew=192)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
平面
;
(2)若
,求二面角
的大小.
![](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/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1633988fd62a652de726ee92a917b52d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dfaefb10f82b89802bb420b3c41de1bd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/48f3c9abbd78e9a6840ee5f30381daac.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/6/235226e4-5388-4c9b-bb30-9a28d68e43b6.png?resizew=192)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/638537c0a30676c73fea76c80e0f8bd0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9af29254fe60a392c249c5791279e9c8.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c06ee08ec4bc31ecf0aa9dbc2d2172fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f06a8da60c3bccd7f150d9ab4e13e09.png)
您最近一年使用:0次
名校
2 . 在正三角形
中,E、F、P分别是
、
、
边上的点,满足
(如下左图).将
沿
折起到
的位置,使二面角
成直二面角,连结
、
(如下右图).
(1)求证:
平面
;
(2)求二面角
的大小(用反三角函数表示).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c06ee44206d4e110610bc412f11f2ab5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c105d6ba18fbb0581fb982175e2eac9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/49b50357a6545cae8348e3059312f520.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/eb2d555062f34d5a74f6d47da4ea8888.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dc14ed237a4bcc35cbd1f5f1321b3718.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d0ff310aabd2282b539537ebed3f788.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/9/21/c0a81532-214a-4d3c-8b67-db39084beadb.png?resizew=286)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c4525c00ed908bed8ba8d353e747a858.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24fac8b38a9cf7602391f6d6ca933bd2.png)
(2)求二面角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8097ceec369f4de5071a58290ce6e7e9.png)
您最近一年使用:0次