\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) =-2\,{\frac {{\frac {\rm d}{{\rm d}x}}y \left( x \right) }{x}}-{\frac {{a}^{2}y \left( x \right) }{{x}^{4}}}=0}
\]