y=sin(2x+兀/6)-cos(2x+兀/3)
=sin(2x+兀/6)-cos(兀/2-(2x-兀/6))
=sin(2x+兀/6)-sin(2x-兀/6)
=2cos[(2x+兀/6+2x-兀/6)/2]sin[(2x+兀/6-2x+兀/6)/2]
=2cos2xsin兀/6
=cos2x
所以最小周期是T=2兀/2=兀
最大值是1
最小值是-1