y''(x)=-\frac{y'(x) \left(-\phi ''(x)-\phi (x) \phi '(x)+\phi \left(x^3\right)\right)}{\phi '(x)+\phi (x)^2}-\frac{y(x) \left(-\phi (x) \phi ''(x)+\phi (x)^2 \left(-\phi '(x)\right)+\phi '(x)^2\right)}{\phi '(x)+\phi (x)^2}