Consider the real-valued function satisfying 2fsinx+fcosx=x Then the

Given 2fsinx+fcosx=x                          1Replacing  x by  π2-x,  we  ge         2fcosx+fsinx=π2-x                        2Eliminating f(cosx) from (l) and (2), we get          3fsinx=3x-π2or    fsinx=x-π6or    f x=sin-1x-π6        fx  has  domain   -1,1.Also,sin-1x∈-π2,π2  or   sin-1x-π6∈-2π3,π3.