F(x)= radical 2sin(x+π/4)= radical 2cos(x-π/4)
When X=0 f(-0)=0
f(-x)= sin(-x)+cos(-x)=-sinx+cosx
And f(-x)=-f(x), so f(x)=sinx-cosx.
f(x)= sinx+cosx x & gt； 0
=0 x=0
sinx-cosx x & lt； 0