已知a,b,c分别为△ABC三个内角A,B,C的对边,acosC+根号下3分之asinC-b=0.(1)求A
问题描述:
已知a,b,c分别为△ABC三个内角A,B,C的对边,acosC+根号下3分之asinC-b=0.(1)求A
(2)若△ABC的面积为根号3,求bsinB+csinC的最小值
答
一问:sinAcosC+√3sinAsinC-sinB-sinC=0sinAcosC+√3sinAsinC-sin(A+C)-sinC=0sinAcosC+√3sinAsinC-sinAcosC-cosAsinC-sinC=0√3sinAsinC-cosAsinC-sinC=0√3sinA=1+cosA因tan(A/2)=(sinA)/(1+cosA...