Consider the non-linear differential equation x y^{\prime \prime}=y^{\prime}+\left(y^{\prime}\right)^{3} Re-write (1) by using the substitution u(x) = y'.%3D After re-organizing the equation you found in (a),we get the differential equation u^{\prime}-x^{-1}

u=x^{-1} u^{3}