SOLUTION: The sum to infinity of a GP is twice the sum of the first two terms. Find possible values of the common ratio.

Question 1163035: The sum to infinity of a GP is twice the sum of the first two terms.
Find possible values of the common ratio.
Answer by greenestamps(13203) (Show Source): You can put this solution on YOUR website!

With first term a and common ratio r....

the sum of the first two terms is ;
the infinite sum is

The condition is that the infinite sum be twice the sum of the first two terms:

or

Both solutions satisfy the condition of the problem.

ANSWER: The possible common ratios are and

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