- #1
urista
- 11
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I'm solving a Helmholtz equation uxx+uyy+lambda*u=0 in a rectangle: 0<=x<=L, 0<=y<=H with the following boundary conditions:
u(x,0)=u(x,H)=0 and ux(0,y)=ux(L,y)=0
I found the eigenvalues to be:
lambda(nm)=(n Pi/L)^2+(m Pi/H)^2
and the eigenfunctions to be:
u(nm)=Cos(n Pi x/L)*Sin(m Pi y/H)
Now the question I'm stuck on is to show that if L=H (a square) then most eigenvalues have more than one eigenfunction
and, Are any two eigenfunctions of this eigenvalue problem orthogonal in a two-dimensional sense?
Any help would be greatly appreciated.
u(x,0)=u(x,H)=0 and ux(0,y)=ux(L,y)=0
I found the eigenvalues to be:
lambda(nm)=(n Pi/L)^2+(m Pi/H)^2
and the eigenfunctions to be:
u(nm)=Cos(n Pi x/L)*Sin(m Pi y/H)
Now the question I'm stuck on is to show that if L=H (a square) then most eigenvalues have more than one eigenfunction
and, Are any two eigenfunctions of this eigenvalue problem orthogonal in a two-dimensional sense?
Any help would be greatly appreciated.