Find the sum
But, we're not quite done yet.
|Our formula only works when||.|
|So, what if r is something like||? Then the series does not have|
|a sum. It shoots off to infinity. When this happens, we call the series "divergent."|
So, if someone asks you to find the sum of an INFINITE geometric sequence, CHECK THE RATIO!
|If||, crunch the sum.|
|If||, say something like|
"There's no finite sum. This critter's divergent!"
Find the sums (if possible):