Posted by Rachel on Monday, May 7, 2012 at 1:58pm.
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
No answer to your question !!!
There is something bogus about your question.
(your last sentence appears incomplete)
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