Let    Â
find a so that f may be derivable at x =1.
Here, f(1) = 1+a
                                  (here  h < 0 1+h < 1)
                           (here h >0 1 + h > 1)
     Â
      Â
  Â
Since f is derivable at x =1
∴   Lf'(1) = Rf'(1)
    1 = 2a         Â
  Â
     Â