Solving Hermite Polynomials: Find Form from Definition

In summary, the conversation discusses the problem of showing that the Hermite polynomials are solutions of the Hermite differential equation. The first step is to find the form of H_n by using the given equation. The speaker shares their attempts at finding the solution, including using the Cauchy product formula, but none have been successful. Finally, they realize that a Taylor expansion is the key to solving the problem.
  • #1
Zorba
77
0
In a past exam paper at my uni I am asked to show that the hermite polynomials are solutions of the hermite diff. equation but first there is the following

[tex]\Phi(x,t)=\exp (2xh-h^2)=\sum_{n=0}^{\infty} \frac{h^n}{n!}H_n(x)[/tex]

So I need to find the form of [tex]H_n[/tex] first, and I'm stuck. I tried writing

[tex]\exp (2xh-h^2)=\exp (2xh) \cdot \exp (-h^2)[/tex]

and then writing both of those as infinite series and using the Cauchy product formula but I couldn't get it to work out. I've tried a variety of other ways, but none seem to give me the proper formulas that I see on wikipedia and so on. So what the approach to take if you a priori know nothing about the Hermite polynomials, and you need to determine their form using the above definition?
 
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  • #2
Ah, damn it, I see it now it's a just a matter of doing a Taylor expansion! :smile:
 

1. What are Hermite polynomials?

Hermite polynomials are a set of orthogonal polynomials that are named after the French mathematician Charles Hermite. They are commonly used in mathematical physics and engineering to solve problems involving differential equations, Gaussian integrals, and other mathematical functions.

2. How do you define Hermite polynomials?

Hermite polynomials can be defined as a series of polynomials that satisfy the following recurrence relation: Hn+1(x) = 2xHn(x) - 2nHn-1(x), with H0(x) = 1 and H1(x) = 2x. They can also be defined using the Rodrigues formula: Hn(x) = (-1)nex2/2(dn/dxn)(e-x2/2).

3. How do you solve Hermite polynomials?

To solve Hermite polynomials, you can use a variety of techniques such as the recurrence relation, the Rodrigues formula, or using the generating function. You can also use numerical methods such as the Gram-Schmidt process or Gaussian quadrature to approximate the solutions.

4. What are the applications of Hermite polynomials?

Hermite polynomials have many applications in mathematics, physics, and engineering. They are commonly used to solve problems involving the Quantum Harmonic Oscillator, the Schrödinger equation, and the Heat equation. They can also be used in probability theory to model random processes and in numerical analysis to approximate solutions of differential equations.

5. Are there any special properties of Hermite polynomials?

Yes, Hermite polynomials have several special properties that make them useful in solving mathematical problems. They are orthogonal, which means that the integral of their product over a certain range is equal to zero. They also have a specific generating function and recurrence relation that can be used to simplify their calculations. Additionally, they have a unique symmetry property that allows for easy manipulation and simplification.

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