Converting a Single ODE to Matrix Form for Eigenvalue Analysis

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Discussion Overview

The discussion revolves around converting a single ordinary differential equation (ODE) into matrix form for the purpose of eigenvalue analysis. The focus is on the transformation of a non-homogeneous second-order ODE into a system suitable for evaluating eigenvalues and eigenvectors.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant presents the ODE \( aY'' + bY' + c = 0 \) and seeks guidance on converting it to matrix form, questioning the inclusion of the non-homogeneous term \( c \).
  • Another participant suggests introducing new variables \( y_1 = Y \) and \( y_2 = \frac{dY}{dx} \) to reformulate the second-order ODE as a system of two first-order ODEs.
  • A later post inquires about the possibility of including the constant \( c \) in the matrix form, suggesting that the matrix form may need to focus on the homogeneous part for eigenvalue analysis.
  • One participant expresses skepticism about whether the eigenvalues would be affected by the constant \( c \), while another agrees that they would not be influenced by it.

Areas of Agreement / Disagreement

Participants express differing views on the treatment of the constant \( c \) in the matrix form. While there is agreement that eigenvalues are not affected by \( c \), the discussion on how to properly convert the ODE into matrix form remains unresolved.

Contextual Notes

The discussion does not resolve the specific method for including the non-homogeneous term in the matrix form or the implications for eigenvalue analysis. There are also assumptions regarding the treatment of the ODE that are not explicitly stated.

SeM
Hi, I have the following ODE:

aY'' + bY' + c = 0

I would like to convert it to a matrix, so to evaluate its eigenvalues and eigenvectors. I have done so for phase.plane system before, however there were two ODEs there. In this case, there is only one, so how does this look like in a matrix form given that this is non homogenous? Is it as such:

\binom{a \ \ 1}{-b \ \ 1}\binom{c}{0}}

Or how is it correct to convert ONE ODE to matrix form, and from there study it?
 
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you can write a second order ode as a system of two first order ode's by introducing new variables:
## y_1 = Y ##
## y_2 = \frac{dY}{dx} ##

such that the original ode becomes:
## a\frac{dy_2}{dx} + by_1 +c = 0##
with the auxiliary ode:
## y_2 = \frac{dy_1}{dx} ##
 
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Thanks!
 
Is there any chance of getting the constant c in the matrix form at all, or should a matrix form rather give the homogenous form in order to solve the eigenvalues?
 
Well, do you think the eigenvalues will change by the constant c?
 
No, they won't indeed! Thanks!
 

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