We now assume $\lambda \neq 0$. Among the solutions of the differential equation (II.1) $$r^2 z''(r) + r z'(r) - \lambda z(r) = 0$$ which are the solutions that extend continuously to 0?
We now assume $\lambda \neq 0$. Among the solutions of the differential equation (II.1)
$$r^2 z''(r) + r z'(r) - \lambda z(r) = 0$$
which are the solutions that extend continuously to 0?