The solution of the differential equation $ydx + (x-y^2)dy = 0$ is
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → $3xy-y^3 = C$: C is an arbitrary constant
Given differential equation: $y\,dx+(x-y^{2})\,dy=0$
Rearrange as a linear equation for $x$ in variable $y$:
$\frac{dx}{dy}= -\frac{x-y^{2}}{y}$
$\frac{dx}{dy}+\frac{1}{y}x = y$
Integrating factor = $e^{\int \frac{1}{y}\,dy}=e^{\ln y}=y$
Multiply both sides by the integrating factor:
$y\frac{dx}{dy}+x = y^{2}$
$\frac{d}{dy}(xy)=y^{2}$
Integrate w.r.t. $y$:
$xy=\frac{y^{3}}{3}+C$
Hence the general solution is:
$xy-\frac{y^{3}}{3}=C$
The general solution of the differential equation is $xy-\frac{y^{3}}{3}=C$.