Using fourier and laplace transform to solve PDE

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Discussion Overview

The discussion revolves around solving a partial differential equation (PDE), specifically a heat equation, using both Fourier and Laplace transforms. Participants explore the methodology of applying these transforms separately and in combination, as well as the implications of doing so.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant notes that many resources provide examples of solving the heat equation using the Fourier transform, but seeks guidance on incorporating both Fourier and Laplace transforms.
  • Another participant suggests that the problem may require applying the Fourier transform with respect to time and the Laplace transform with respect to space, questioning if both can be combined in one solution.
  • A third participant emphasizes that the Fourier transform is defined over the entire real line, while the Laplace transform is defined only for non-negative values, proposing that the Fourier transform should be applied in space and the Laplace transform in time to derive a polynomial equation in two variables.
  • One participant seeks clarification on whether the transforms must be performed independently in time and space and asks what information can be derived from this approach.

Areas of Agreement / Disagreement

Participants express differing views on the application of Fourier and Laplace transforms, with no consensus on the best approach or the implications of combining the two methods. The discussion remains unresolved regarding the specific methodology and outcomes.

Contextual Notes

There are limitations in the discussion regarding the assumptions made about the transforms, the definitions of the variables involved, and the potential outcomes of combining the two methods. These aspects remain unresolved.

cyw1984
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PDE is type of heat equation.

Many book only gives an example of solving heat equation using Fourier transform.
An exercise asks me to solve it for using Fourier and laplace transform:

In the heat equation, we'd take the Fourier transform with respect to x for
each term in the equation. How to combine it with using Fourier and laplace transform

Can anyone suggest some example and notes to me??
 
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umum...the question mention us to use Fourier and laplace transform. Is there mention us to use Fourier transform with respect to t (t>0) and then inverse Fourier transform to solve the solution; Separately, solve the question using laplace transform with respect to x -\infty< x < \infty and then inverse laplace transform?

Can there combines two transformation in one??
What is the result compared with two method??
 
It's all the way around... The Fourier transform is defined in \mathbb{R}, while the Laplace transform is defined in \mathbb{R}^+, so you have to take the Fourier transform in space and the Laplace transform in time. That way, you will land with a polinomial equation in two variables, which will give you some sort of dispersion relation.
 
AiRAVATA said:
It's all the way around... The Fourier transform is defined in \mathbb{R}, while the Laplace transform is defined in \mathbb{R}^+, so you have to take the Fourier transform in space and the Laplace transform in time. That way, you will land with a polinomial equation in two variables, which will give you some sort of dispersion relation.

O...
you mean that it must need to do it independent in two times??

What information will give in this type of question??
 

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