Extrema
An extremum is a largest or smallest value of some process. In the language of mathematics, a process is described by a function. Accordingly, we introduce the concept of extremum of a function
Then we present methods to detect extrema. Let us begin by giving the precise definition of "extremum of a function":
Detecting local extrema A convenient tool to detect local extrema of a function f of one variable is the second derivative test. In order to formulate a second derivative test for functions of several variables, we require the concept of a Hesse matrix.
