y=sin(π/3-2x)
=-sin(2x-π/3)
∴y=sin(π/3-2x)的减区间是
-π/2≤2x-π/3≤π/2
π/2≤2x≤3π/2
π/4≤x≤3π/4
那么y=sin(π/3-2x)在(-π/2.π/2)上的减区间
是[π/4,π/2)