f(x)=√3sinx/4cosx/4+1/2cos2x/4 =√3/2·sin(2x/4)+1/2cos(2x/4) =cos(π/6)sin(x/2)+sin(π/6)cos(x/2) =sin(x/2+π/6)最小正周期=4π最大值=1最小值=-1
