# Geometric sequenses with ln

#### hostergaard

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...

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#### yyat

Hint: Simplify the sum using ln(a)+ln(b)=ln(a*b). You will not need the geometric series.

#### hostergaard

ohh, i get it. The the answer is ln(x70/y34)
Right?
Thanks for the help! you are great! #### yyat

ohh, i get it. The the answer is ln(x70/y34)
Right?
Thanks for the help! you are great! 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.
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