# Math Help - Binomial Theorem with fractional exponents

1. ## Binomial Theorem with fractional exponents

What's the 3rd term of (8x-y)^(1/3)?

Can you use the binomial theorem for this? Because I dont know how you can find out the coefficient. Because you cant find out $((1/3) choose 2)$. So how would you find the answer?

2. actually you can, but it's not easy ... finding factorials of fractions involves the Gamma function if I remember correctly.

3. Hello,

${r \choose n}=\frac{1}{n!} \prod_{k=0}^{n-1} (r-k)=\frac{(r-1)(r-2)\dots(r-n+1)}{n!}$

Here, n=2 and r=1/3