I Expressing a differential equation into a different format

[Shovon00000]

How do we express this differential equation (dy/dx)= (y/x) + tan(y/x) into this form( Mdx + Ndy=0) where M,N are functions of (x,y) ?

 

[anuttarasammyak]

\frac{dy}{dx}=\frac{y}{x}+\tan\frac{y}{x}=-\frac{M}{N}
why do not you make
M=\frac{y}{x}+\tan \frac{y}{x},N=-1