Question 673222
<pre>
The second term in a geometric series is 36. The 
sum of the first two terms is -18. What is the first 
term and the common ratio? 

what is the sum to infinity of the series?

Let the first term be x.

The sum of the first two terms is 18

So 

x + 36 = 18
     x = -18

Common ratio = {{{(second_term)/(first_term)}}} = {{{36/(-18)}}} = -2

Therefore the sum to infinity is undefined because in order to
have a sum to infinity, the common ratio must be between -1 and 1,
exclusive of both.

Edwin</pre>