Question

How do you find the sum of the infinite geometric series given `a_1=18` and r=-1.5?

Answer 1

This Geometric series will not have a "sum", since the `|-1.5|` = 1.5 which is greater than 1.

Explanation:

This means that the terms, although alternating positive and negative, will grow larger and larger, thus producing an infinite sum.

If the `|r| <1`, you can then compute the sum with the formula: `S_oo=(a_1)/(1-r)`.