f(x)=1-2sin^2(x+π/8)+2sin(x+π/8)*cos(x+π/8)
=cos(2x+π/4)+sin(2x+π/4)
=√2sin(2x+π/4+π/4)
=√2cos2x
f(x)=√2cos2x的最小值即cos2x=-1时
f(x)的最小值为 -√2
递增区间为[-π/2+kπ,kπ] (k∈Z)
f(x)=1-2sin^2(x+π/8)+2sin(x+π/8)*cos(x+π/8)
=cos(2x+π/4)+sin(2x+π/4)
=√2sin(2x+π/4+π/4)
=√2cos2x
f(x)=√2cos2x的最小值即cos2x=-1时
f(x)的最小值为 -√2
递增区间为[-π/2+kπ,kπ] (k∈Z)