1 . 已知
的三边长
,三内角为
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7f5573b30734d65648f61c0a94c98de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38335830b93ac4d99c28a8e209eecb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7b102b36cba4c1868afcd7a591a796da.png)
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2 . 在
中,角
所对的边分别为
,且
.
(1)判断
的形状,并加以证明;
(2)当
时,求
周长的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38335830b93ac4d99c28a8e209eecb3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7f5573b30734d65648f61c0a94c98de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/748d27f8027ed7b499ba7db2f2e49081.png)
(1)判断
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4580cc037c0c760c728cdbb74a8154c6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
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解题方法
3 . 在△ABC中,角A,B,C的对边分别为a,b,c,已知C=2B.
(1)若
,求
的值;
(2)若
,求证:
.(参考数据:
)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51ece8120d3b6ad7b2995de8dae6ac90.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51c181f86de3c96a7ef7a1a04c3a438f.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/069390dd908ff203327958117a226593.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/07d1f6a78ba819d5fbd4e66fd03ea8dc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8d7b2946445e885458481a436fdcafb1.png)
您最近一年使用:0次
2022-06-30更新
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617次组卷
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3卷引用:安徽省太和中学2022-2023学年高二上学期数学竞赛试卷
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