名校
1 . 正
的边长为1,中心为O,过O的动直线l与边AB,AC分别相交于点M、N,
,
,
.给出下列四个结论:
①
;
②若
,则
;
③
不是定值,与直线l的位置有关;
④
与
的面积之比的最小值为
.
其中所有正确结论的序号是______ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3abd34df1150309cb07ac490e493abf8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bbb8904776ef2199390ad6eeecbb187.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbbf438660d3f1d1df13b7abb7db8c68.png)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbf09a57c67f3ac18a94bf82bb1c0820.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/52c27334d7a603d274af7e73585a991a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2e4561e47a142958c953fd14a5494bda.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/587b693b82241eb9c32cdbb96c209f33.png)
④
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98013a5042685a1db94249e70c62c09a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d86ab7c97cd8a0b15ba5efc1be94230.png)
其中所有正确结论的序号是
您最近一年使用:0次
解题方法
2 .
外接圆圆心为O,且
,则![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27ba370a3912d1a983146af9c7f9c950.png)
___________ .
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0b5b59beabd101e3df40df813bf41b7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/27ba370a3912d1a983146af9c7f9c950.png)
您最近一年使用:0次