Solving two simultaneous integro-differential equations

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Discussion Overview

The discussion revolves around finding a closed-form analytical solution for two simultaneous integro-differential equations involving functions u[x] and v[x]. The equations include integral terms and are subject to specific initial conditions, with the parameters a, b, f, g, and e being positive constants. The scope includes theoretical exploration and numerical methods for solving the equations.

Discussion Character

  • Exploratory
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant expresses the challenge of finding a closed-form analytical solution for the given integro-differential equations.
  • Another participant suggests that an analytical expression for the equations is unlikely to be found.
  • A different participant proposes differentiating one of the equations with respect to x to derive an integro-differential equation for a single function, implying a potential pathway to a solution.
  • A later reply indicates that, after modifications to the equations, a numerical solution was successfully obtained using Mathematica's NDSolve command.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the feasibility of finding an analytical solution, with some expressing skepticism while others explore alternative methods. The discussion includes both theoretical and numerical approaches without a definitive resolution.

Contextual Notes

The discussion highlights the complexity of the integro-differential equations and the potential limitations in finding analytical solutions, as well as the reliance on numerical methods for practical resolution.

Boudy
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I am trying to find a closed-form (analytical) solution for the two following simultaneous integro-differential equations :

du[x]/dx= - a v[x] +b ∫〖[1-(y-x)^4 〗].(v[y]-v[x])dy
And
(dv[x])/dx= - f u[x] -g ∫〖[1-(y-x)^4 〗].u[y]dy
With the initial conditions:
v[0]=e and u[1]=0
a,b,f,g and e are positive constants
Both integrals are from y=0 to y=1.
The unknowns are u[x] and v[x].
 
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an analytical expression for that set of equations is most likely not going to be found.
 
Just wrote down the start to a solution.
Differentiate one of the equations with respect to x. You already have expressions for du/dx and dv/dx, so when you differentiate you can substitute the other equation in. Voila! Suddenly you've got an integro-differential equation for only one function. I'll leave you to do the rest of it ;)
 
I thank both friends for their kind help. Fortunately, and after some modifications in the equations, a solution was possible using the numerical solution of two simultaneous differential equations in two variables and one single independent variable. This was done using the NDSolve command within a Mathematica 11 code.
Thanks again.
 

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