\[
\boxed{
h \left( {\frac {\rm d}{{\rm d}x}}y \left( x \right)  \right) {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) +j \left( y \left( x \right)  \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) +f=0}
\]