\[
\boxed{
{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left( x \right) -{a}^{2}{\frac {\rm d}{{\rm d}x}}y \left( x \right) -{{\rm e}^{2\,ax}} \left( \sin \left( x \right)  \right) ^{2}=0}
\]