# Homework Help: Power series

1. Mar 17, 2005

### stunner5000pt

can someone tell mehow to expand $$(1 - \frac{2n}{(n+1)^2})^2$$ into power series

or at least direct me to the formula!!

2. Mar 17, 2005

### stunner5000pt

actaully i wnated to investigate $$\lim_{n \rightarrow \infty} (1- \frac{1}{2} (\frac{n-1}{n+1})^2$$ but i used L'Hopital's rule and found that it would be 1/2.

Thanks anyway!