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Homework Help: Geometric sequenses with ln

  1. Feb 24, 2009 #1
    1. The problem statement, all variables and given/known data

    http://img16.imageshack.us/img16/2327/nummer1.jpg [Broken]

    2. Relevant equations
    Sn=(u1(rn-1))/(r-1)

    3. The attempt at a solution
    I think i need to use the equation for geometric series(above). Or do i use the arithmetic furmula since ln(a/b)=ln(a)-ln(b). I think i am a bit confused...
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 24, 2009 #2
    Hint: Simplify the sum using ln(a)+ln(b)=ln(a*b). You will not need the geometric series.
     
  4. Feb 24, 2009 #3
    ohh, i get it. The the answer is ln(x70/y34)
    Right?
    Thanks for the help! you are great!:wink:
     
  5. Feb 24, 2009 #4
    Well, in the denominator you should have y*(y^2)*(y^3)*...*(y^34)=y^595. Here I am using the formula 1+2+3+...+n=n(n+1)/2.
    Glad I could help. :smile:
     
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