由正弦定理b/sinB=c/sinC故 sinC=c*sinB/b=√3m又c<b,故C<B<π/2,sinC>0所以 C=arcsin(√3m)又由A+B+C=π ,∠B=π/3得 A+C=2π/3即 A=2π/3-arcsin(√3m)