SOLUTION: The sum of 1 + r + r^2 + r^3 + .... = 1.85. What is the value of the sum r + r^3 + r^5 + r^7....?

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Question 1104515: The sum of 1 + r + r^2 + r^3 + .... = 1.85. What is the value of the sum r + r^3 + r^5 + r^7....?
Answer by greenestamps(13200) About Me  (Show Source):
You can put this solution on YOUR website!


The sum of an infinite geometric series with first term a and common ratio r (|r|<1) is

S+=+a%2F%281-r%29

We are told that
1%2F%281-r%29+=+1.85
1.85-1.85r+=+1
1.85r+=+.85
r+=+.85%2F1.85+=+17%2F37

The series whose sum we are to find has first term r and common ratio r^2; the sum of that infinite series is