函数f(x)=(sinx+cosx)^2-2sin^2x的单调递增区间为?

函数f(x)=(sinx+cosx)^2-2sin^2x的单调递增区间为?
函数f(x)=(sinx+cosx)^2-2sin^2x的单调递增区间为?

函数f(x)=(sinx+cosx)^2-2sin^2x的单调递增区间为?
f=1+sin2x-1+cos2x=sin(2x+pi/4)
增区间为[-3/8pi+npi,1pi/8+npi]