I'm stuck on b) iii) of this question. I'll show you what i have got so far.

the function f is given by f(x)=

a) express f(x) as a partial fraction.

I got

b) i) Find the first three terms in the expansion of

I got

b) ii) Obtain a similar expansion for

I got

where i am stuck on is b) iii)

Hence, or otherwise, obtain the first three terms in the expansion of f(x) in ascending powers of x