解题方法
1 . 已知△ABC的内角A,B,C所对的边分别为a,b,c,①若
=
=
,则△ABC一定是等边三角形;②若acos A=bcos B,则△ABC一定是等腰三角形;③若bcos C+ccos B=b,则△ABC一定是等腰三角形;④若a2+b2-c2>0,则△ABC一定是锐角三角形.上面四个结论正确的是( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37bae33441773f20041b0fe0db280d9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2480128316e89616facd9f2e72cf82c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddf262214d500e53d5b0093c3be69f83.png)
A.① | B.② | C.③ | D.④ |
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