Heaviside's Method for Regular Singular Points

In summary, the conversation discusses the criteria for a regular singular point, which requires both p and q to be finite as x approaches x_0. It also clarifies that x=0 is a regular singular point for a and c, but not for d. Additionally, there is a suggestion to revise the definition to include the requirement that at least one of the limits of p and q must not exist for x_0 to be considered a singular point.
  • #1
Ted123
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  • #2
You should have y''+ py'+ qy= 0 and (x- x_0)^2q(x) finite. You have left out the "q"s. Also, you say that x_0 is a regular singular point if those are finite. In order that x_0 be a singular point, at least one of the two limits of p and q, as x goes to x_0 must not exist.

Yes, from what you have, x= 0 is a regular singular point for a and c, it not a regular singular point for d. But I would say that x= 0 is not even a singular point for b.
 
  • #3
HallsofIvy said:
You should have y''+ py'+ qy= 0 and (x- x_0)^2q(x) finite. You have left out the "q"s. Also, you say that x_0 is a regular singular point if those are finite. In order that x_0 be a singular point, at least one of the two limits of p and q, as x goes to x_0 must not exist.

Yes, from what you have, x= 0 is a regular singular point for a and c, it not a regular singular point for d. But I would say that x= 0 is not even a singular point for b.

Yes, I accidently missed the q's. And thanks for the explanation. I think the definition should read 'A singular point x_0 is called regular if both those are finite as x-> x_0.'
 

FAQ: Heaviside's Method for Regular Singular Points

What is a regular singular point?

A regular singular point is a point in a differential equation where the solution can be expressed as a power series. It is called "regular" because the power series has a finite radius of convergence and does not have any singularities at the point.

How is a regular singular point different from an irregular singular point?

A regular singular point is a point where the solution can be expressed as a power series, while an irregular singular point is a point where the solution cannot be expressed as a power series and may have infinite or non-integer powers.

What types of differential equations have regular singular points?

Ordinary differential equations (ODEs) and partial differential equations (PDEs) can both have regular singular points. However, ODEs are more commonly studied in the context of regular singular points.

How is a regular singular point determined in a differential equation?

A regular singular point can be determined by examining the coefficients of the highest and second-highest order derivatives in the differential equation. If these coefficients are not constants, then the point is a regular singular point.

What are some applications of regular singular points in science and engineering?

Regular singular points have applications in a variety of fields, including physics, engineering, and biology. They can be used to model physical systems and phenomena, such as the motion of a pendulum or the behavior of electrical circuits. They also have applications in the solution of differential equations in quantum mechanics and relativity.

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