# Math Help - General formula for the expansion of binomials with non-integer indices

1. ## General formula for the expansion of binomials with non-integer indices

I'm familiar with binomial expansions in the form of $(a+b)^n$, where n is an integer. However, today I came across the following:
$\sqrt[3]{1+\frac{1}{n^3}} \:=\: 1+\frac{1}{3n^3}+\frac{1}{9n^6}+\frac{5}{81n^9} + \ldots$

How is that result reached? Is there a general expression for the expansion of $(a+b)^n$ where n is not an integer?

(I searched online, but I didn't find anything that explained what I was after.)

2. Search for Newton's Generalised Binomial Series.