OK, this is going to blow your mind! In this section, I'm going to add up an infinite number of numbers -- all positive -- and get a FINITE answer!
Think about it...
If you add these guys... forever...
The answer would be infinite -- right?
Well, I'm going to get a number. Just wait. We'll get to it in awhile.
First, let's check out the sigma notation for geometric sequences:
Here's an example:
Find the sigma notation for
* hint: Find r first, then get the nth term formula.