(1)f(x)=2sin^2x+cos^2x-sinxcosx=sin^2x+sin^2x+cos^2x-sinxcosx=1+sin^2x-sinxcosx=1+1/2-1/2cos2x-1/2sin2x=3/2-1/2(sin2x+cos2x)=3/2-根号2/2sin(2x+π/4)2x的周期为2π,即x的周期为π2nπ-π/2≤2x+π/4≤2nπ+...