1.

After multiplying the equation by y, we have M = 2 x y3 - y2and N = 3 x2 y2 - 2 x y + 2 y. My = 6 x y2 - 2 y = Nxso this makes the DE exact, i.e. y is an integrating factor of the original DE. $F(x,y) = \int M \, dx = x^2 y^3 - x y^2 + h(y)$.

\begin{displaymath}N = 3 x^2 y^2 - 2 x y + 2 y = \frac{\partial F}{\partial y} = 3 x^2 y^2 - 2 x y +
h'(y) \end{displaymath}

So h'(y) = 2 y. We take h(y) = y2, so the solutions are x2 y3 - x y2 + y2 = constant.




Robert Israel
2002-02-07