1. m*n=2根3sinB/2*cosB/2+根3/2=根3 根3sinB=根3/2 sinB=1/2 B=30度或150度2. B=30度 a=6 S=1/2a*c*sinB c=4根3 b^2=a^2+c^2-2accosB=36+48-2*6*4根3 *根3/2=66b=根号66
