$\displaystyle
xyy'=\frac{x^2}{cos(\frac{y}{x})}+y^2
$
i know i need to look for a variable which both its derivative and him selft are present in the equation.
i tried t=y/x
but its derivative is not present in the equation
??
$\displaystyle
xyy'=\frac{x^2}{cos(\frac{y}{x})}+y^2
$
i know i need to look for a variable which both its derivative and him selft are present in the equation.
i tried t=y/x
but its derivative is not present in the equation
??