(1)向量m·向量n = √3(sinAcosB + cosAsinB) = √3sin(A+B) = √3sinC,而cos(A+B) = -cosC∵m·n=1+cos(A+B) ,∴√3sinC + cosC = 1 = 2·sin[C + (π/6)] ,∴sin[C+(π/6)] = 1/2 ,而[C + π/6]∈(π/6 ,7π/6) ,...