# More About Derivatives (Part 2)

Notation: The derivative $$f'(x)$$ of a function $$f(x)$$ is also denoted as

$\frac{df}{dx} (x)$

This notation comes from the fact that when you compute the derivative, you compute

$\frac{df}{dx}(x_0) = \displaystyle\lim_{x\to x_0} \frac{f(x)-f(x_0)}{x-x_0}$

The term $$f(x)-f(x_0)$$ is usually referred as $$\Delta f$$, and the term $$x-x_0$$ is referred as $$\Delta x$$. So, sometimes, in some books (specially Physics books) you’re going to find the definition