y=sin(π/3-2x)+sin2x =根号3/2cos2x-1/2sin2x+sin2x =根号3/2cos2x+1/2sin2x =sin(2x+π/3)最小值是:-1
y=sin2x-sin(2x-60)=sin(2x-30+30)-sin(2x-30-30)=2cos(2x-30)sin30=cos(2x-30)当定义域为R时最小值-1
楼上做的都是正确的但是要声明π是弧度,如果没有就写最小值为-2sin(π/6)