How do you find the sum of the infinite geometric series 1.02 + 2.04 + 4.08 + 8.16 +…?

1 Answer
Nov 14, 2015

You don't.

Explanation:

You can only find the sum of an infinite geometric series if the ratio between each term is between -1 and 1. Or, with more rigor,

#-1 < r < 1#

In that case the formula for the sum would be

#(a_0 - a_nr)/(1-r)#

Where #a_0# is the first term and #a_n# is the nth term.

If #r# is between -1 and 1, then #a_n# will be so small you can disconsider it and find the infinite sum.