SOLUTION: The four term of a G.p is 56 while the six term is 7/8.Find the G.p and hence sum to infinity

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Question 1049605: The four term of a G.p is 56 while the six term is 7/8.Find the G.p and hence sum to infinity
Answer by stanbon(75887) About Me  (Show Source):
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The four term of a G.p is 56 while the six term is 7/8.Find the G.p and hence sum to infinity
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g(4) = a*r^3 = 56
g(6) = a*r^5 = 7/8
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Divide g(6) by g(4) to get r^2 = (7/8)/56 = 1/(8^2)
r = 1/8
Solve for "a"::
a*r^3 = 56
a = 56/(1/8)^3 = 28672
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Sum to infinity:: = a/(1-r) = 28673/(7/8) = 32768
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Cheers,
Stan H.
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