Solving Second Order Inhomogeneous Equations with ODEs

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Discussion Overview

The discussion revolves around solving a second-order inhomogeneous ordinary differential equation (ODE) of the form d²y/dx² + k*dy/dx = du/dx + u. Participants explore various methods and approaches to tackle this equation, including traditional techniques and potential transformations.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Mathematical reasoning

Main Points Raised

  • One participant requests hints for solving the inhomogeneous equation using ODE techniques.
  • Another participant asserts that it is not possible to solve a single differential equation for two different functions, implying a limitation in the problem's formulation.
  • A different viewpoint suggests that the method of Frobenius might be applicable, although it acknowledges the challenge of having three different variables complicating traditional methods.
  • Another participant proposes the idea of reworking the equation into a partial differential equation, indicating that while it may not yield a neat solution for u and y, it could provide a general understanding of the solution.
  • One participant interprets the equation as representing a dynamic system, suggesting the use of Laplace transforms to derive a transfer function from u to y, while noting the necessity of knowing u(x) and the initial conditions for y.

Areas of Agreement / Disagreement

Participants express differing views on the solvability of the equation and the appropriate methods to apply, indicating that multiple competing approaches remain without a consensus on the best path forward.

Contextual Notes

There are unresolved assumptions regarding the nature of the functions involved and the initial conditions necessary for certain methods, which may affect the applicability of the proposed solutions.

Who May Find This Useful

This discussion may be of interest to those studying differential equations, particularly in the context of inhomogeneous equations and dynamic systems in engineering or applied mathematics.

naxiaodong
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d2y/dx2+k*dy/dx = du/dx+u

anyone got a hint how to use ODE to sovle this inhomogenous equation?

Thanks a lot
 
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You can't solve a single differential equation for two different functions any more than you can solve a single algebraic equation for two different numbers.
 
I would say that you may be able to solve this using the method of Frobenius, which ultimately means that you break it down into a root series problem. Although, I believe the person above me was correct in saying that you cannot solve this using traditional methods since you have three different variables.
 
hmm I wonder if its possibly to rework this into a partial differential equation for x that is a function of u and y, while not giving you a nice litle functionfor u and y it will give you a general idea of the solution.
 
This equation seems to represent a dynamic system, where u is the input and y the output.
You can use Laplace transforms to get a transfer function from u to y.
To solve for y you must know the function u(x) and the initial conditions y(0) and y'(0).
 

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