Eigenfunction expansion in Legendre polynomials

hi10
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Homework Statement



How to use eigenfunction expansion in Legendre polynomials to find the bounded solution of
(1-x^2)f'' - 2xf' + f = 6 - x - 15x^2 on -1<= x <= 1

Homework Equations



eigenfunction expansion

The Attempt at a Solution



[r(x)y']' + [ q(x) + λ p(x) ] = f(x)
In this case, r = 1-x^2 , q = 1 , p = 0 , f = 6 - x -15 x^2 , r(-1) = r (1) = 0

Thanks for any help!
 

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First what are the eigenfunctions you want to use? In other words, what are the solutions to Legendre's equation.
 
I have the same problem.

the attachment from hi10 is what i was thinking.

Does anyone know what u(x) is in hi10's post for determining what an is?
 
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...
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