f（x）=sin2xcos2x-根号3sin²2x
=(1/2)sin4x-√3(1-cos4x)/2
=(1/2)sin4x+(√3/2)cos4x-√3/2
=sin4xcosπ/3+cos4xsinπ/3 -√3/2
=sin(4x+π/3)-√3/2
所以f（x）的最小正周期2π/4=π/2.