SOLUTION: What is the sum of the geometric sequence 1, 4, 16, ... if there are 8 terms?

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Question 773410: What is the sum of the geometric sequence 1, 4, 16, ... if there are 8 terms?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
What is the sum of the geometric sequence 1, 4, 16, ... if there are 8 terms?
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n = 8 ; a = 1 ; r = 4/1 = 4
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S(n) = a[(r^n-1]/[r-1]
S(8) = 1[255/3] = 85
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Cheers,
Stan H.
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