Inhomogeneous wave equation help

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Discussion Overview

The discussion revolves around solving the inhomogeneous wave equation 3Utt + 10Uxt + 3Uxx = sin(x+t). Participants explore methods to find a particular solution after identifying the homogeneous part of the equation.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant presents the homogeneous solution as U(x,t) = f(3x-t) + g(x-3t) and seeks further guidance on finding a particular solution.
  • Another participant suggests using a trial solution of the form U_{p}(x,t) = A\sin(x+t) to determine the coefficient "A".
  • A participant expresses relief at the simplicity of the problem after arriving at a final solution of U(x,t) = f(3x-t) + g(x-3t) - sin(x+t)/16.
  • There is a reiteration of the trial solution approach, with an additional suggestion to include a cosine term, U_{p}(x,t) = A\sin(x+t) + B\cos(x+t), leading to a discussion about the coefficient B being zero.

Areas of Agreement / Disagreement

Participants generally agree on the approach of using trial solutions, but there is some variation in the proposed forms of these solutions and the coefficients involved.

Contextual Notes

There is an assumption that the participants are familiar with the methods of solving wave equations, and the discussion does not resolve the specifics of determining the coefficients in the trial solutions.

finmath
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I need help solving 3Utt+10Uxt+3Uxx=sin(x+t)

I have found the homogeneous part, which is U(x,t)=f(3x-t) +g(x-3t), but I don't know where to go from there. Any help would be much appreciated!
 
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Well, make a trial solution [tex]U_{p}(x,t)=A\sin(x+t)[/tex] and see if you can determine what "A" must be. :smile:
 
Back to the basics! For some reason I thought it was going to be way more difficult.
My final solution is U(x,t)=f(3x-t) + g(x-3t) - sin(x+t)/16

Thanks for your help! :smile:
 
arildno said:
Well, make a trial solution [tex]U_{p}(x,t)=A\sin(x+t)[/tex] and see if you can determine what "A" must be. :smile:

I though the try function should be of the form

[tex]U_{p}(x,t)=A\sin(x+t) + B\cos(x+t)[/tex]
 
And B will be 0..:smile:
 

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