For example, if we have a function $f(x) = x^2$, then its derivative with respect to $x$ is $f'(x) = 2x$. This means that the instantaneous rate of change of $f(x)$ with respect to $x$ is $2x$.
Differentiation is a fundamental operation in calculus and is used to find slopes of tangent lines, rates of change, and many other important mathematical concepts.