I know it is convergent by I cannot determine why

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Homework Help Overview

The problem involves determining the convergence or divergence of the series from 0 to infinity of the expression 6/(4n-1) - 6/(4n+3). The original poster asserts that the series is convergent but is unsure of the reasoning behind this conclusion.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Some participants suggest exploring whether the series might be a telescoping series. Others mention that algebraic manipulation could help demonstrate convergence, providing a specific algebraic transformation of the series.

Discussion Status

Participants are actively discussing algebraic approaches to understanding the convergence of the series. There is acknowledgment of different methods, including telescoping and comparison tests, but no consensus has been reached on a definitive approach.

Contextual Notes

There is an indication that the original poster is working under homework constraints, which may limit the exploration of certain methods or assumptions.

golb0016
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Homework Statement


0 to infinity sum of 6/(4n-1)-6/(4n+3)
Determine if the series is convergent or divergent.

The Attempt at a Solution


I know it is convergent by I cannot determine why.
 
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Did you try to see if it might be a telescoping series?
 


With some algebra, you should be able to show that the series converges. For example, with the particular series in question we can show that:

\frac{6}{4n -1} - \frac{6}{4n + 3} = 6 \left(\frac{(4n + 3) - (4n - 1)}{(4n + 3)(4n - 1)}\right) = 6\left(\frac{4}{(4n + 3)(4n - 1)}\right)

Using a little bit more algebra, you should easily be able to determine that the series is convergent.

Edit: Oops, somebody got here first. Sorry Dick!
 


jgens said:
With some algebra, you should be able to show that the series converges. For example, with the particular series in question we can show that:

\frac{6}{4n -1} - \frac{6}{4n + 3} = 6 \left(\frac{(4n + 3) - (4n - 1)}{(4n + 3)(4n - 1)}\right) = 6\left(\frac{4}{(4n + 3)(4n - 1)}\right)

Using a little bit more algebra, you should easily be able to determine that the series is convergent.

Edit: Oops, somebody got here first. Sorry Dick!

Apologies never necessarily. Besides, you showed how a similar series would converge even if it doesn't telescope using a comparison test. That's a different answer.
 

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