Solutions around ordinary points

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In summary, if we have a well behaved, second order, linear, homogeneous, ordinary differential equation with all ordinary points, and we are seeking an ordinary solution about ##x_0 = 0##, the solution takes the form of an infinite sum with coefficients ##a_n## that can be determined using a recurrence relation. However, if we choose ##x_0 = (a \neq 0) \in \mathbb{R}## instead, the solution will still take the same form, but the infinite sum will be divided into two sums for even and odd index terms.
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I did this quite a while ago, and I wanted to know something specific.

Suppose we have a well behaved, second order, linear, homogeneous, ordinary differential equation. Suppose further all points are ordinary, and so we can seek an ordinary solution about ##x_0 = 0##. Then the solution takes the form:

$$y = \sum_{n = 0}^{\infty} a_n (x - x_0)^n = \sum_{n = 0}^{\infty} a_n x^n = \sum_{k = 0}^{\infty} a_{2k} x^{2k} + \sum_{k = 0}^{\infty} a_{2k + 1} x^{2k + 1}$$

Where we may deduce ##a_n## from a recurrence relation on ##n##.

Now my question is, if I chose ##x_0 = (a \neq 0) \in \mathbb{R}## instead of ##x_0 = 0##, would the solution take the form:

$$y = \sum_{n = 0}^{\infty} a_n (x - x_0)^n = \sum_{n = 0}^{\infty} a_n (x - a)^n = \sum_{k = 0}^{\infty} a_{2k} (x - a)^{2k} + \sum_{k = 0}^{\infty} a_{2k + 1} (x - a)^{2k + 1}$$

?

Thank you.
 
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Yes: all that is happening is the infinite sum is being divided into two sums, even index terms and odd index terms.
 

1. What are solutions around ordinary points?

Solutions around ordinary points refer to the behavior of solutions to a differential equation near a point where the equation is well-behaved and has a unique solution. These solutions can be approximated by Taylor series expansion and are typically smooth and continuous.

2. How are solutions around ordinary points different from solutions around singular points?

Solutions around ordinary points differ from solutions around singular points in that they are well-behaved and have a unique solution, while solutions around singular points may not have a unique solution or may be discontinuous.

3. Can solutions around ordinary points be approximated?

Yes, solutions around ordinary points can be approximated using Taylor series expansion. This allows us to find an expression for the solution in terms of derivatives at the point, providing a way to approximate the behavior of the solution near the ordinary point.

4. Are solutions around ordinary points always smooth and continuous?

In most cases, solutions around ordinary points are smooth and continuous. However, there may be cases where the solution is not smooth, such as when there is a discontinuity or singularity at the ordinary point.

5. How can solutions around ordinary points be used in practical applications?

Solutions around ordinary points can be used to approximate and understand the behavior of a system in practical applications. They can also be used to validate and improve mathematical models of physical systems by comparing the solutions from the model to the actual behavior near ordinary points.

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