SOLUTION: how many terms has a G.P whose second term is 1/2 and the common ratio and the last term are 1/2 and 1/120 respectively
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Question 938153: how many terms has a G.P whose second term is 1/2 and the common ratio and the last term are 1/2 and 1/120 respectively
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
how many terms has a G.P whose second term is 1/2 and the common ratio and the last term are 1/2 and 1/120 respectively
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a(2) = ar = 1/2
Since r = 1/2, a = 1
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Last term = a(n) = ar^(n-1) = 1*(1/2)^(n-1) = 1/120
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Solve:: (1/2)^(n-1) = 1/120
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(n-1)log(1/2) = log(1/120)
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n-1 = log(1/120)/log(1/2) = 6.90
n = 7.90
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Comment:: That answer has to be a whole number.
Did you post the problem correctly?
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Cheers,
Stan H.
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