Help getting started with this differential equation

In summary, the conversation discusses a problem involving the equation ∂2Φ/∂s2 + (1/s)*∂Φ/ds - C = 0, where s is a radial coordinate and C is a constant. The method of undetermined coefficients is suggested as a possible approach to finding a general solution, and it is noted that the equation can be simplified to a first-order equation by substituting Psi = dPhi/ds. The use of partial derivative symbols is questioned as there is only one variable involved.
  • #1
Daniel Sellers
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TL;DR Summary
I have a fairly simple non-homogeneous second order ODE to solve but I can't seem to get started with it.
I need to solve

2Φ/∂s2 + (1/s)*∂Φ/ds - C = 0

Where s is a radial coordinate and C is a constant.

I know this is fairly simple but I haven't had to solve a problem like this in a long time. Can someone advise me on how to begin working towards a general solution?

Is the method of undetermined coefficients the correct approach?

Thanks very much.
 
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  • #2
Substituting ##\Psi=d\Phi/ds## turns your equation into the first order equation ##\Psi'(s)+\frac{1}{s}\Psi(s)=C##. You should be able to do this with an integrating factor.
 
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  • #3
The equation is the same as $$\frac{1}{s}\frac{\partial}{\partial s}\left(s\frac{\partial \phi}{\partial s}\right)=C$$
 
Last edited:
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  • #4
Is there a reason for the partial derivative symbols when there is only the single variable s?
 
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1. What is a differential equation?

A differential equation is a mathematical equation that relates the rate of change of a variable to the value of the variable itself. It is used to model various natural phenomena in fields such as physics, engineering, and economics.

2. How do I solve a differential equation?

The method for solving a differential equation depends on its type and complexity. Some common techniques include separation of variables, substitution, and using differential equation solvers. It is important to first identify the type of differential equation and then choose an appropriate method for solving it.

3. What are the applications of differential equations?

Differential equations have numerous applications in the fields of science and engineering. They are used to model physical processes such as motion, heat transfer, and population dynamics. They are also used in economics, biology, and other areas to study complex systems.

4. What is the order of a differential equation?

The order of a differential equation is the highest derivative present in the equation. For example, a first-order differential equation contains only first derivatives, while a second-order differential equation contains second derivatives.

5. How can I check if my solution to a differential equation is correct?

One way to check the correctness of a solution to a differential equation is to plug it back into the original equation and see if it satisfies the equation. Another method is to use initial or boundary conditions to verify the solution. Additionally, there are various software tools that can be used to check the accuracy of a solution.

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