\sum_{n=2}^{\infty} \begin{pmatrix} {n}\\ {2} \end{pmatrix} z^{n}
Dec 28, 2010 #1 geft 148 0 [tex]\sum_{n=2}^{\infty} \begin{pmatrix} {n}\\ {2} \end{pmatrix} z^{n}[/tex]
Dec 28, 2010 #2 Office_Shredder Staff Emeritus Science Advisor Gold Member 2021 Award 5,020 1,007 Which part is confusing you?
Dec 28, 2010 #3 geft 148 0 It's supposed to be a power series, but I don't understand how to decipher the brackets.
Dec 28, 2010 #4 micromass Staff Emeritus Science Advisor Homework Helper Insights Author 22,129 3,301 It's a binomial coefficient. It's defined as [tex]\binom{n}{k}=\frac{n!}{k!(n-k)!}[/tex] See http://en.wikipedia.org/wiki/Binomial_coefficient
It's a binomial coefficient. It's defined as [tex]\binom{n}{k}=\frac{n!}{k!(n-k)!}[/tex] See http://en.wikipedia.org/wiki/Binomial_coefficient