(2sinC-sinA)cosB-sinBcosA=0
2sinCcosB-(sinAcosB+sinBcosA)=0
2sinCcosB-sinC=0
所以cosB=1/2,B=60°.
√3sinA+sin(C-30°)=√3sinA+sin(120°-A-30°)
=√3sinA+sin(90°-A)
=√3sinA+cosA
=2sin(A+30°)
因为0°所以30°1/纯哪雹2