\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) =-{\frac {\sin \left( x \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) }{\cos \left( x \right) }}-1/4\,{\frac { \left( 2\,{x}^{2}+{x}^{2} \left( \sin \left( x \right)  \right) ^{2}-24\, \left( \cos \left( x \right)  \right) ^{2} \right) y \left( x \right) }{{x}^{2} \left( \cos \left( x \right)  \right) ^{2}}}+\sqrt {\cos \left( x \right) }=0}
\]