Is the Frobenius Method Required at Each Singular Point for General Solutions?

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Discussion Overview

The discussion revolves around the necessity of applying the Frobenius method at each singular point when solving differential equations with regular singular points. Participants explore the implications of using this method for general solutions, particularly in the context of initial and boundary value problems.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant questions whether the Frobenius method must be applied at each singular point for a general solution, suggesting a need for clarification.
  • Another participant proposes that it may be possible to avoid using the Frobenius method altogether, citing the example of Legendre's equation, which can be solved around an ordinary point instead of singular points.
  • A different viewpoint suggests that the Frobenius method is typically necessary at singular points only when initial conditions are specified at those points, as it facilitates the application of series solutions.
  • One participant raises a concern regarding boundary value problems, questioning whether separate series solutions are needed when conditions are given at two different points.

Areas of Agreement / Disagreement

Participants express differing opinions on the necessity of the Frobenius method at singular points, with no consensus reached on whether it is required for general solutions in all cases.

Contextual Notes

Participants mention specific types of problems (initial value vs. boundary value) and the implications of these on the use of the Frobenius method, indicating a potential dependence on problem context and definitions.

ductape
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Hello, I was just wondering, if I have a differential equation that has two regular singular points, and I am asked for the general solution, do I need to use the Frobenius method about each point separately? I suspect that I do I just want to clarify.
Thanks
 
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I think you have the option even not to use the Frobenius method. Can we avoid the regular point?

The Legendre's equation
(1-x2)y" - 2xy' + n(n+1)y = 0
have two regular points but we usually solve the equation about the ordinary point x=0.
 
Typically, we have to use Frobenious method at singular points only when we are given intial conditions at that singular point. It is easier to apply "y(x0)" and "y'(x0)" if our series solution is in terms of (x- x0)n.
 
Yes it looks reasonable to used frobenius series for an initial value problem because of an infinite number of terms involve.

But what about a boundary value problem where we are given two points? y(x0) = y0 and y(x1) = y1 .

We still need to sum an infinite series. :confused:
Is this what ductape meant in the initial post? Used two separate series.
 

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