Zeta function and summation convergence

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Discussion Overview

The discussion revolves around the convergence of the series ∑(k=1 to k=∞)[(((-1)^k) ζ(k))/(e^k)], particularly considering the implications of ζ(1) being infinite and the conditions for alternating series convergence.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions the convergence of the series, noting that while ζ(1) is infinite, the series meets the conditions for convergence of an alternating series.
  • Another participant asks how the original sum was derived, indicating a desire for clarity on the formulation.
  • A different participant suggests applying the ratio test to determine convergence, implying that there are methods available to analyze the series.
  • A later reply reiterates the convergence of a modified series starting from k=2, but highlights that the k=1 term poses a problem for the original series.
  • One participant recalls that the series may relate to a Taylor series of the digamma function, suggesting a potential connection to known mathematical functions.

Areas of Agreement / Disagreement

Participants express differing views on the convergence of the original series, with some suggesting it converges under certain conditions while others point out the problematic nature of the k=1 term. No consensus is reached regarding the overall convergence of the original series.

Contextual Notes

The discussion highlights the dependence on the behavior of ζ(k) as k approaches 1 and the implications of its divergence at that point. The application of convergence tests remains unresolved.

rman144
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I need to know if the following series converges:

∑(k=1 to k=oo)[(((-1)^k) ζ(k))/(e^k)]


The problem is that zeta(1)=oo; however, the equation satisfies the conditions of convergence for an alternating series [the limit as k->oo=0 and each term is smaller than the last.]

Any thoughts?
 
Last edited:
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How did you arrive at the sum?
 
well yeah I see what you're saying about zeta of 1. To see if the summation converges, try one of the tests, like tha ratio test.
 
rman144 said:
I need to know if the following series converges:

∑(k=1 to k=oo)[(((-1)^k) ζ(k))/(e^k)]


The problem is that zeta(1)=oo; however, the equation satisfies the conditions of convergence for an alternating series [the limit as k->oo=0 and each term is smaller than the last.]

Any thoughts?

This one converges
[tex] \sum_{k=2}^\infty \frac{(-1)^k \zeta(k)}{e^k}[/tex]

But in the original zeries, the [tex]k=1[/tex] term is the problem.
 
Yes if memory serves me right that sum is just a constant and an x away from being a taylor series of the digamma function.
 

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