f（x）=1-2sin平方（x+π/8）+2sin（x+π/8）点乘cos（x+π/8）=cos(2x+π/4)+sin(2x+π/4)=√2sin(2x+π/2)=√2cos2xf（x）的最大值√2,2x=2nπ;x=nπ单调递增区间 2x∈[(2n-1)π,2nπ]x∈[(2n-1)π/2,nπ]...