Understanding Geometric Sequences with ln

[hostergaard]

Homework Statement

http://img16.imageshack.us/img16/2327/nummer1.jpg

Homework Equations

S_n=(u₁(rⁿ-1))/(r-1)

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...

 

[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.
Glad I could help.