Expert: Bobby Soltani - 2/15/2005

Question
Hello Bobby, just wanted to inquire on how you would solve the problem below:

Find the sum of the geometric series:
(0.993)+(0.993)^2+(0.993)^3+...

Thanks

Brad  

Answer
Hi Brad,

When we have a geometric series of the form:

nth term = ar^n-1

the sum is S = a/(1-r)

In our series however, the first term which is 1 is missing.  So, when we use the formula, we must subtract 1 from the final answer.

For our problem, a = 1 and r = 0.993

So, S = 1/(1-0.993) - 1 = 141.86

Let me know if you have questions.

Bobby