# The Geometric Series Formula (VIDEO!)

What is the geometric series formula? When is it valid? How do we derive the formula?

In this video we use a paper-tearing trick to show that the infinite formula is valid at least for some types of numbers (and this trick makes it so obvious that the formula is true in these cases. It’s neat!) We then discuss how to prove the formula true in general and for what range of values it holds. All easy and all fun!