SOLUTION: A geometric sequence has all positive terms. The sum of the first two terms is 15 and the sum of infinity is 27. Find the value of
(a) The common ratio;
(b) The first term;
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Sequences-and-series
-> SOLUTION: A geometric sequence has all positive terms. The sum of the first two terms is 15 and the sum of infinity is 27. Find the value of
(a) The common ratio;
(b) The first term;
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Question 392679: A geometric sequence has all positive terms. The sum of the first two terms is 15 and the sum of infinity is 27. Find the value of
(a) The common ratio;
(b) The first term;
Thank you :) Answer by ewatrrr(24785) (Show Source):
Hi
sum of the first two terms is 15 for a geometric series , where r is the common ratio
27 = 15/(1-r^2)
1-r^2 = 15/27
r^2 = 12/27 = 4/9
r = 2/3 sequence has all positive terms..tossing out negative solution for r
(b) The first term;
