calculation – Taylor Series, exponential function


Determine the derivative f ^ (2) (0) of the function (e ^ x-1) / x
I am really lost to find the answer to this question. I found the Taylor series for the function:
1 + 1 / 2x + 1 / 6x ^ 2 + 1 / 24x ^ 3 …
Although I'm not sure, why this is true …
I don't have a good approach to this kind of problem, so I hope someone explains it to me 🙂