已知函数f(x)=-根号(2)sin(2x+π/4)+6sinxcosx-2cosx^2+1,x属于R,求f(x)最小正周期

题目

已知函数f(x)=-根号(2)sin(2x+π/4)+6sinxcosx-2cosx^2+1,x属于R,求f(x)最小正周期

答案

f(x)=-√2sin(2x+π/4)+6sinxcosx-2cosx^2+1,
=-sin2x-cos2x+3sin2x-cos2x,
=2sin2x-2cos2x
=2√2sin(2x-π/4)
最小正周期T=π