Why Do We Need to Convert Series to Partial Fractions for Evaluation?

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Homework Help Overview

The discussion revolves around the evaluation of infinite series, specifically focusing on the need to convert certain series into partial fractions for simplification. The original poster questions the reasoning behind this process using the series \(\sum_{k=1}^{\infty} \frac{1}{k(k+3)}\) as an example.

Discussion Character

  • Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the method of using partial fractions to evaluate series, with some noting that it can lead to a telescoping series. Questions arise about the implications of the form of the partial fractions and how they affect the telescoping nature of the series.

Discussion Status

The discussion is active, with participants providing insights into the benefits of partial fractions for evaluating series. There is a recognition of the conditions under which telescoping occurs, though no consensus has been reached regarding the necessity of a negative sign in the partial fractions.

Contextual Notes

Participants are examining the definitions and characteristics of telescoping series, indicating a focus on the underlying principles rather than specific solutions. The original poster's inquiry suggests a desire for deeper understanding of the conversion process and its implications.

trap101
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Now yesterday I got help in realizing how to evaluate the sums of certain series, but while doing it I never got the reason behind why we take a series such as: [itex]\sum[/itex] from k=1 to ∞ 1/k(k+3), I know how to solve the sum, but why do we have to convert it to a set of partial fractions in order to do it?
 
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It's the simplest way of finding the limit of its partial sums, by the telescoping series.
 
sharks said:
It's the simplest way of finding the limit of its partial sums, by the telescoping series.

ok, but what happens if the partial fraction that you end up with doesn't have a minus sign in it, then how would the telescoping occur?
 
trap101 said:
ok, but what happens if the partial fraction that you end up with doesn't have a minus sign in it, then how would the telescoping occur?
In that case, it would not be a telescoping series.

The definition of the telescoping series is that the limit of the partial sums must be equal to the sum of the first and last terms only.
 

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