The general solution of the differential equation $y(x^2+y+e^x) dx-e^x dy = 0 , $ is |
$x^3y-3e^x=Cy$ $x^3y+3e^x=3Cy$ $y^3x-3e^y =Cx$ $y^3x+3e^y = Cx$ |
$x^3y+3e^x=3Cy$ |
The correct answer is option (2) : $x^3y+3e^x=3Cy$ We have, $y(x^2+y+e^x) dx-e^x dy = 0 $ $⇒x^2y^2d\, x + y \, e^x dx-e^x dy =0$ $⇒x^2dx +\frac{ye^xdx-e^x\, dy}{y^2}= 0 $ $⇒x^2dx+d\left(\frac{e^x}{y}\right) = 0 $ On integrating, we get $\frac{x^3}{3}+\frac{e^x}{y} = C $ $⇒x^3 y + 3e^x = 3 Cy$ |