Help!! Geometric progression

Question(1):A G.P has a common ratio of 2 find the value of 'n' for which the sum 2n terms is 33 times the sum of n??
Question(2):in A G.P the product of the 2nd and the 4thterm is double ,the 5th term and the sum of the first 4 term is 80.find the G.P??

asked by Collins
  1. r=2, so you want

    a(2^(2n)-1) = 33a(2^n-1)
    n=5

    ar * ar^3 = 2ar^4
    a(r^4-1)/(r-1) = 80

    a=2, r=3
    GP: 2,6,18,54,162

    posted by Steve
  2. When the 8th term of a G.P is divided by the 3rd term, the result is 32 and the 11th term Of the sequence is 4096. Find the c'mon ratio, the first term and the sequence..

    posted by Emmrex

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