## Calculus (3rd Edition)

$$\frac{dy}{dx}=\frac{x^2}{y^2}.$$
By differentiating the equation $x^3-y^3=4$ with respect to $x$, we get $$3x^2-3y^2\frac{dy}{dx}=0\Longrightarrow \frac{dy}{dx}=\frac{x^2}{y^2}.$$