\[
\boxed{
{\frac {\rm d}{{\rm d}x}}y \left( x \right) -{\frac {1}{\sqrt {{\it a4}\,{x}^{4}+{\it a3}\,{x}^{3}+{\it a2}\,{x}^{2}+{\it a1}\,x+{\it a0}}}}=0}
\]