f(x)=2√2cos(x+π/4)cos(x-π/4)+2√2sinxcosx=2√2sin[π/2-(x+π/4)]cos(x-π/4)+2√2sinxcosx=-2√2sin(x-π/4)cos(x-π/4)+2√2sinxcosx=√2sin2x-√2sin(2x-π/2)=√2sin2x+√2cos2x=2(√2/2sin2x+√2/2cos2x)...