f(x)=sin−1⁡2x1+x2 is differentiable on

f(x)=sin−12x1+x2⇒f'x=11−2x1+x22ddx2x1+x2                     = 1+x21+x22−4x2.1+x2.2−2x2x1+x22                   = 11−x2221−x21+x2                 = 21+x2    if  x<1−21+x2   if  x>1∴f'x  does not exist at x=1, i.e x=±1∴f(x) is differentiable on R−−1,1.