Since at x = 0, there is a part where taking out x^n and leaving behind (f(x) / x) ^n, this caused a undefined value since when x = 0, there f(0) / 0 is undefined.
... so that the coefficients of the Taylor series are found symply expanding (1)...
... so that is...
... as awkward found...
From your original post:
So is the coefficient of in the series for f(x).
But the problem did not ask for a general form of the coefficient, it simply asked for the value of
which can be found without necessarily finding the general coefficient.