How Do You Find the First Three Terms of 1/f(x) and Expand e^e^x?

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Hi everyone, I am completely stuck on the below problem. Would anyone like to give me a hint?

This is the problem:

Let

f(x) = \sum {a(i)*x^(i)}

for i=0 up to infinity

given that f(0)= 0 , find the first three terms in the Taylor expansion about
x = 0 of the function 1/f(x) .

Thanks a lot!:smile:

PS: also, for the expansion of e^{e^(x)} is it OK to simply expand the entire function in one go by differentiating the entire thing (which is what I did) or does one have to split it up somehow?
 
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Improve your notation first.
 
I tried to do it with latex but I don't know how to do sums? And strangely if I put Latex brackets around the first expression it generates a different image,namely exp^{exp^{x}}, instead of the sum formula. This is all very odd!
 
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