The derivative of a function is a second function showing the rate of change of the dependent variable compared to the independent variable. It can be thought of as a graph of the slope of the function from which it is derived. The process of finding a derivative is called differentiation. The derivative of y with respect to x (denoted as y') is equal to
The inverse of differentiation is integration.
For multivariable scalar fields, either a gradient (a vector field representing the direction of greatest change) or directional derivative (a scalar representing the rate of change in a particular direction) can be taken. The two equivalents to derivation over a scalar field are divergence and curl.