Geometric series

A geometric series has first term a and common ratio r. Choose values for a, r and the number of terms, n, and look at the series displayed.
You will also be given the sum of the first n terms, S_n,and the value of .
What values of r make S_n and the value of similar?

Summary

Make sure you fully understand how these formulas work:
• each term of a geometric series can be expressed as ar^n-1.
• the sum of n terms of a geometric series can be expressed as .
• the sum of an infinite geometric series can be expressed as , when |r| < 1.