Posted by Rachel on Monday, May 7, 2012 at 1:58pm.
5+(5/2)+(5/4)
Sn=189
Find n for the given sum if the geometric series

Algebra 2  Reiny, Monday, May 7, 2012 at 2:08pm
looks like
a = 5 and r = 1/2
so 5((1  (1/2)^n)/(1(1/2)) = 189
1  (1/2)^n = 56.7
(1/2)^n = 56.7
since we know that n must be a whole number and for the above to be true, n must be odd
so we could solve
(1/2)^n = 56.7
using logs,
n = log 56.7/log .5 = a negative
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