Show that the Hermite polynomials H2(x) and H3(x).

ASIWYFA
Messages
3
Reaction score
0
Hi guys. I am new, and i need help badly. I have been asked this question and I have no idea how to do it. Any help would be appreciated!



Show that the Hermite polynomials H2(x) and H3(x) are orthogonal on
x € [-L, L], where L > 0 is a constant,
H2(x) = 4x² - 2 and H3(x) = 8x³ - 12x

Thanks in advance.
 
Physics news on Phys.org
You need to show that

\int_{-L}^L{(4x^2-2)(8x^3-12x)dx}=0

This seems an easy integral...

Or do you consider another inner product??
 
Yes you are correct. THanks you. I believe I have solved the problem correctly.
 
One thing that's worth pointing out about this problem is that while there are other ways for functions to be orthogonal over a specific interval (like [-1,1] for example), the only way possible for functions to be orthogonal over the arbitrary interval [-L,L] is if their product is an odd function.

So the original question is equivalent to showing that the product of H2 and H3 is an odd function.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
Back
Top