This has been bothering me for a while. I've seen many different versions of this and I'd just like to get the following cleared up. Is the following true?(adsbygoogle = window.adsbygoogle || []).push({});

[tex]

\sum\limits_{k = 0}^N {r^k } = \frac{{1 - r^{N + 1} }}{{1 - r}}

[/tex]

There are other related things I am slightly worried about but I can't remember what they are at the moment so I might post them later. In the mean time, any verification of the above formula that I have quoted would be good thanks.

**Physics Forums | Science Articles, Homework Help, Discussion**

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Geometric series

**Physics Forums | Science Articles, Homework Help, Discussion**