Solving PDE: Is There a General Method or Just Guesswork?

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Discussion Overview

The discussion revolves around the methods for solving partial differential equations (PDEs), questioning whether there exists a general method applicable to all types of PDEs or if solutions are primarily derived from guesswork. The scope includes theoretical aspects of PDE classification and solution techniques.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants assert that there is no general method for solving all PDEs, particularly nonlinear ones, suggesting that classification is the primary approach used by mathematicians.
  • Others inquire specifically about linear PDEs, seeking clarification on whether a general method exists for this category.
  • One participant proposes that for linear PDEs, methods such as bringing equations to canonical form, analyzing their type (hyperbolic, elliptic, parabolic), and applying various techniques (Green's functions, separation of variables, Fourier/Laplace transforms) can be effective, but emphasizes that solutions depend on specific cases.

Areas of Agreement / Disagreement

Participants express differing views on the existence of a general method for solving PDEs. While some agree that linear PDEs can be approached with established techniques, there is no consensus on a universal method applicable to all PDEs, particularly nonlinear ones.

Contextual Notes

The discussion highlights limitations in the generalizability of methods for solving PDEs, particularly regarding the classification and specific conditions required for different types of equations. The dependence on boundary conditions and the nature of the equations is also noted.

ksoy
[SOLVED] Solving PDE

I am just wondering, is there any gerneral method in solving PDE's or just by guess works??

thanks...
 
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ksoy said:
I am just wondering, is there any gerneral method in solving PDE's or just by guess works??

thanks...

In mathematics there's no room for "guessing".
As for PDE-s,well,mathematicians found a way to classificate them.So far (and more than surely in the future) there has't been found a general method to solving PDE-s,that is to aapply successfully for every kind of PDE.
For example,for nonlinear PDE-s,there is no general method of solving.Analitically,of course.I assume that was the initial question about.
Try to solve (or imagine a way to tackling) somthing like that
[tex]\frac{u^{3}(x,y,z)}{xy^{\frac{6}{3}}z}[\frac{\partial^{5} u(x,y,z)}{\partial x^{5}}]^{7}+5 u^{8}(x,y,z)-12x^{7}y^{\frac{3}{4}}z=0[/tex]
 
how about linear PDE??
Is there a general method of solving them??
 
ksoy said:
how about linear PDE??
Is there a general method of solving them??

Yes,for the linear case,there is.Try first of all to bring them to the canonical form.From there analyze the type (hyperboli,elliptic,parabolic) for every point in the domain of the unknown function.Then look very carefully at the geberal problem and its conditions (boundary type (Dirichlet/Neumann),or initial). Several methods come up then.Green function methods,variable separation methods,Fourier/Laplace transform methods,and so on.
Some equation,after being put in the canonical form may admit immediate integration,and the famous example is the unidimensional wave equation.

Anyway,all these depend from case to case.
 

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