f(x)=sin(π/3+x)cos(π/3-x)-sinxcosx+1/4
=1/2[sin(π/3+x+π/3-x)+sin(π/3+x-π/3+x)]-sinxcosx+1/4
=1/2(sin2π/3+sin2x)-1/2*2sinxcosx+1/4
=1/2sin2π/3+1/4
题有误,
f(x)=sin(π/3+x)cos(π/3-x)-sinxcosx+1/4
-sinxcosx应该 +inxcosx