It is said that $\frac{d}{dx}$ is a operator and $\frac{dy}{dx}$ is the derivative of y with respect to x. But now in thomas calculus he defined $\frac{dy}{dx}$ as the ratio of two quantities dy and dx,where dy and dx are differentials.
What is the difference between operator $\frac{d}{dx}$ and differentials?
How is a derivative is defined in terms of differentials? Please anyone help?
