YOUR TURN:
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!"
TRY IT:
Find the sums (if possible):