Limit involving dirac delta distributions

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Discussion Overview

The discussion revolves around evaluating the limit involving the second derivative of the Dirac delta distribution, specifically the expression \(\lim_{x\to 0^{+}} \frac{\delta''(x)}{\delta''(x)}\) and later corrected to \(\lim_{x\to 0^{+}} \frac{\delta'(x)}{\delta''(x)}\). Participants explore the implications of this limit in the context of mathematical rigor and the nature of distributions.

Discussion Character

  • Exploratory
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant questions whether the limit is impossible to evaluate, suggesting that the limiting behavior of a Dirac distribution may not be meaningful.
  • Another participant proposes using a Gaussian approximation to express the delta function, potentially to facilitate the evaluation of the limit.
  • A different participant expresses skepticism about the validity of the limit itself, indicating that it may not make sense in a rigorous mathematical context.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the validity or evaluability of the limit. There are competing views regarding the interpretation and mathematical soundness of the expression.

Contextual Notes

There are unresolved assumptions regarding the treatment of distributions and the mathematical framework within which the limit is being evaluated. The discussion reflects a lack of clarity on the definitions and properties of the Dirac delta function and its derivatives.

thrillhouse86
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Hey All,

I am trying to evaluate the limit:
[tex] \lim_{x\to 0^{+}} \frac{\delta''(x)}{\delta''(x)}[/tex]

Where [tex]\delta'(x)[/tex] is the first derivative of the dirac distribution and [tex]\delta''(x)[/tex] is the second derivative of the dirac distribution.

I thought about the fact that this expression will be infinity / infinity and then using L'Hospitals but that doesn't help.

I guess my question (as someone with an engineering / physics background and not a mathematician) is this limit impossible to evaulate ? and if so is it impossible because taking the limiting value of a dirac distribution doesn't make a whole lot of sense ?

Thanks
 
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Sorry I mean to evaulate:
[tex] \lim_{x\to 0^{+}} \frac{\delta'(x)}{\delta''(x)}[/tex]
 
Try writing the delta function as limit of a Gaussian, for example.
 
Where did this limit come from? I don't believe it even makes sense...
 

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