How do you find the sum of the infinite geometric series -2+1-1/2+...?
The formula for the sum of a geometric series is
Let's look at the terms to find out what the ratio is. Divide
The ratio is
So, let's plug our ratio into the formula:
Be careful here - this is the sum of a series whose first term is the ratio itself. In other words, this is the sum of the series
To get the correct sum, all we need to do is add