Does This Series Telesope and What is Its Partial Sum Formula?

In summary, the conversation is about finding a formula for the partial sum of a given series and determining its limit. The participants are struggling to show that the series telescopes and are discussing the given hint of 1-1/k^2 = (k+1)(k-1)/k^2. The conversation ends with a question about what ln(1-2/k^2) is equal to.
  • #1
Firepanda
430
0
I've been asked to show that the series:

http://img260.imageshack.us/img260/2676/asdaam0.jpg

That it telescopes, hence find a forumla for its partial sum, and then state the limit.

I'm sure I could find a formula for its partial sum IF I could simply show that it telescopes, for me I can't see how it does. Maybe I have a wrong definition of telescoping, but I thought it was when the majority of terms cancel, where in that series I can't see happening. Also I believe from inspection the limit is (ln 1).

Any help? :)

Thanks
 
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  • #2
It might help to notice that 1-1/k^2 = (k+1)(k-1)/k^2.
 
  • #3
Yeah they gave us that as a hint. I can't see how it helps though :P
 
  • #4
So
[tex]ln(1-\frac{2}{k^2})= ln(\frac{(k-1)(k+1)}{k^2}[/tex]
What is THAT equal to?
 

FAQ: Does This Series Telesope and What is Its Partial Sum Formula?

1. What is the formula for its partial sum?

The formula for the partial sum of a series is Sn = a1 + a2 + ... + an, where Sn is the sum of the first n terms in the series and a1, a2, ..., an are the individual terms in the series.

2. How do you find the partial sum of a series?

To find the partial sum of a series, you can use the formula Sn = a1 + a2 + ... + an, where Sn is the sum of the first n terms in the series and a1, a2, ..., an are the individual terms in the series. You can also use a calculator or a spreadsheet to help you calculate the partial sum.

3. Can the formula for the partial sum be applied to any series?

Yes, the formula for the partial sum can be applied to any series as long as the series has a finite number of terms. However, for infinite series, the formula may not work as the sum of the series may not converge.

4. How is the formula for the partial sum derived?

The formula for the partial sum is derived from the concept of a limit. Essentially, as n approaches infinity, the partial sum Sn approaches the sum of the entire series. This is why the formula works for finite series, but may not work for infinite series.

5. Can the formula for the partial sum be used to find the sum of an infinite series?

No, the formula for the partial sum can only be used to find the sum of finite series. For infinite series, the sum may not converge and thus, the formula will not work. Other methods, such as the ratio or root test, may be used to determine the convergence of an infinite series.

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