\begin{equation} x^{2}y’’ + xy’ + (x^{2}-n^{2})y = 0 \end{equation}

this function is very useful, they have no well defined elementary result.

\begin{equation} x^{2}y’’ + xy’ + (x^{2}-n^{2})y = 0 \end{equation}

this function is very useful, they have no well defined elementary result.