Dirac delta function is continuous and differential

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Discussion Overview

The discussion revolves around the properties of the Dirac delta function, particularly its continuity and differentiability. Participants explore its nature as a distribution rather than a traditional function and provide examples that approach the Dirac delta function.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants assert that the Dirac delta function is a distribution and question the meaning of "differentiable" and "continuous" in this context.
  • One participant expresses certainty about the differentiability of the Dirac delta function but has doubts regarding its continuity.
  • Examples of functions that approximate the Dirac delta function are mentioned, including the top hat function and the Gaussian function as their widths approach zero.
  • Another participant notes that while the top hat function is not differentiable, the Gaussian function is differentiable in the limit.
  • There is a discussion about the independence of internal parameters in the Dirac delta function and its properties of continuity and integrability.

Areas of Agreement / Disagreement

Participants express differing views on the continuity of the Dirac delta function, with some asserting it is continuous while others remain uncertain. The discussion includes multiple competing perspectives on its differentiability and the nature of examples provided.

Contextual Notes

Participants highlight the need for careful definitions when discussing the properties of the Dirac delta function, particularly in the context of distributions versus traditional functions. There is also mention of unresolved mathematical nuances regarding the limits of the functions that approximate the Dirac delta.

astro2cosmos
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since dirac delta function is not a literally a function but a limit of function,does it mean that dirac delta function is continuous and differentiable through out the infinity?
is there any example of dirac delta function if yes then give meeeeeeee?
 
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astro2cosmos -> Strictly speaking, the Dirac delta is a distribution, that is it's a functional on the space of smooth and compactly supported functions. As such, one has to be a bit careful as to what does it mean for it to be "differentiable" and "continuous". Still, it is both differentiable and continuous. (I'm sure about differentiability, but have a doubt about continuity...)
is there any example of dirac delta function if yes then give meeeeeeee?
What is that supposed to mean?
 
I don't know how to write in latex but examples of dirac delta are the top hat function as the width goes to zero and the (properly normalised) gaussian as the width goes to zero.
 
astro2cosmos said:
since dirac delta function is not a literally a function but a limit of function,does it mean that dirac delta function is continuous and differentiable through out the infinity?
is there any example of dirac delta function if yes then give meeeeeeee?

The internal parameter that goes to zero inside the dirac delta is INDEPENDENT of the variable parameter that goes to zero in the calculus process. For any given value of the internal parameter (it is never exactly zero), the dirac delta function is continuous, differentialbe, and integrable as far as calculus is concerned.
 
Here's what I learned in my course. There are several functions which in a certain limit approach the dirac delta. The examples I gave are the top hat and the gaussian. The top hat is not differentiable, but the gaussian is. I don't know much more than that.
 

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