f(x)=sin(x+π/2)sin(x-2π).
=cosx(-sinx).
=-sinxcosx.
=-(1/2)sin2x.
1) ∵-1≤sin2x≤1,
∴f(x)max=-(1/2)*(-1)=1/2.
f(x)min=-(1/2)*1=-1/2.
最小正周期T=2π/2=π ；
2）f(π/6)+f(π/12)=-(1/2)[sin2*(π/6)+sin2*(π/12)].
=-√3/4-1/4.
=-(1/4)(√3+1)