SOLUTION: Common radio of the following GP and the number of terms 10/7,1.…...343/1000

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Question 1084169: Common radio of the following GP and the number of terms 10/7,1.…...343/1000
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
10/7,1.…...343/1000
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common ratio = r = 1/(10/7) = 7/10
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a(n) = a(1)*r^(n-1)
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Solve for "n"::
343/1000 = (10/7)*(7/10)^(n-1)
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343/1000 = 1*(7/10)^(n-2)
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(n-2)log(7/10) = log(343/1000)
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n-2 = log(0.343)/log(0.7)
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n-2 = 3
Ans: n = 5
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