(a+b+c)/(sinA+sinB+sinC)=2R怎么证明?

来源：学生作业帮助网编辑：作业帮时间：2024/05/15 08:43:20

(a+b+c)/(sinA+sinB+sinC)=2R怎么证明?
(a+b+c)/(sinA+sinB+sinC)=2R
怎么证明?

(a+b+c)/(sinA+sinB+sinC)=2R怎么证明?
正弦定理:a/sinA=b/sinB=c/sinC=2R
(a+b+c)/(sinA+sinB+sinC)=(2R sinA+2R sinB+2RsinC)/(sinA+sinB+sinC)
=2R (sinA+sinB+sinC)/(sinA+sinB+sinC)
=2R