sin(a+60)+sina=sinacos60+cosasin60+sina=1/2sina+√3/2cosa+sina=3/2sina+√3/2cosa=√3(√3/2sina+1/2cosa)=√3(sina60sina+cos60cosa)=√3(cos60cosa+sina60sina)=√3cos(60-a)=√3cos(180-120-a)=√3cos(180-12...