SOLUTION: The 2nd and 5th term of a geometric progression are 1 and1/8 respectively find Common ratio 8th term First term Sum of the first 8th term

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Question 1177010: The 2nd and 5th term of a geometric progression are 1 and1/8 respectively find
Common ratio
8th term
First term
Sum of the first 8th term
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!

Hi
a%5Bn%5D+=+a%5B1%5D%2Ar%5E%28n-1%29
a%5B2%5D+=+a%5B1%5D%2Ar%5E%28n-1%29 = 1  
          a%5B1%5D+=+1%2Fr+   0r r = +1%2Fa%5B1%5D
a%5B5%5D+=+a%5B1%5D%2Ar%5E%28n-1%29 = 1/8
            %28a%5B1%5D%29%2A+%281%2Fa%5B1%5D%29%5E4+=+1%2F8+   a%5B1%5D = 2
  2r = 1 , r = 1/2

 2(1/2)^4 = 1/8  checks
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