I've got the equation $\phi''+2\phi'+\lambda \phi=0$ where $0<\phi<\pi$ with boundary conditions $\phi(0)=0$ and $\phi'(\pi)+2\phi(\pi)=0$
I've shown its a S-L problem and written the equation in adjoint form, as well as written down the orthogonality property with it's eigenfunctions. I've been told Eigenvalues > unity can be found by writing $\lambda = 1 +\Omega^2$.
How would I derive an equation satisfied by $\Omega$ as well as using a graph to show theres an infinite number of eigenvalues as well as their associated eigenfunctions?