名校
解题方法
1 . 已知四边形
为矩形,
,E为
的中点,将
沿
折起,连接
,
,得到四棱锥
,M为
的中点,
与平面
所成角为
,在翻折过程中,下列四个命题正确的序号是________ .
①
平面
;
②三棱锥
的体积最大值为
;
③点M的轨迹是圆的一部分,且
;
④一定存在某个位置,使
;
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/abc28e69c1ba0aac981256887f7dfa94.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f460edcced5597615113c0fdc95b1dfc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6e490f703eb6c9bb1278c78ebc2d661.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e26d9636ad77369535852c6e4493446a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/552a56a0fa0d1f3ed4cb201f1f0fbbf4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9ce1b066f8869d0ff4513f7a99745125.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5d8d90d123fec1ae1b7b30dac9f88e05.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/657dffbd3623b705f871878fbd9df57e.png)
②三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/16be140caa12effe2ccbdddcbf4db4aa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24c14ff9b66f21c05e52dc3c8908c2df.png)
③点M的轨迹是圆的一部分,且
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/840639b286d7e3f1eb46675dec13e506.png)
④一定存在某个位置,使
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2181c78134c310f746eab44b9124e63b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/21/9eca66e0-e8fd-42ac-8941-442647875e65.png?resizew=220)
您最近一年使用:0次