f(x)=-2cos^2x+2sinxcosx+1=-2(1-cos2x)/2+sin2x+1=sin2x-cos2x=√2sin(2x-π/4)最小正周期 T=2π/2=π最大值=√2x∈R-π/2≤（2x-π/4 ）≤π/2 即：-π/8≤x≤3π/8时,f（x）单调递增π/2≤（2x-π/4 ）≤3π/2 即...