\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) =-1/4\,{\frac { \left( a{x}^{2}+a-3 \right) y \left( x \right) }{ \left( {x}^{2}+1 \right) ^{2}}}=0}
\]