# Can you make sure I'm doing this right?

1. Dec 12, 2011

### Jamin2112

1. The problem statement, all variables and given/known data

2. Relevant equations

If |z|>1, the series ∑z-n converges to 1/(z-1)

If |z|<1, the series ∑zn converges to 1/(1-z)

3. The attempt at a solution

????? Am I getting there?

2. Dec 12, 2011

### spamiam

I don't think that equation is right... Shouldn't it be for |z|>1,
$$\sum_{n=0}^\infty \frac{1}{z^n} = \frac{1}{1-\frac{1}{z}} = \frac{z}{z-1} \; \; ?$$

Or am I missing something?