Bessel function of the second kind

Summary

The Bessel function of the second kind $Y_\nu$ is a second solution of Bessel's equation, independent of the Bessel function of the first kind $J_\nu$. It is also called the Weber function or the Neumann function, and it is sometimes written $N_\nu$. Unlike $J_\nu$, it is unbounded near $0$. Together, $J_\nu$ and $Y_\nu$ span all solutions of Bessel's equation.