The author of my textbook asks to verify that the function:
$ y = \sqrt{ \frac{2}{3} \ln{(1 + x^2)} + C} $
solves the differential equation
$ \frac{dy}{dx} = \frac{x^3}{y + yx^3}$
However, this is an error and this $y$ does not solve the differential equation. Is there a simple typo that makes the problem workable?