Editing Function (mathematics) (section)

===Functions of more than one variable===
In some cases the argument of a function may be an ordered pair of elements taken from some set or sets. For example, a function {{mvar|f}} can be defined as mapping any pair of real numbers <math>(x, y)</math> to the sum of their squares, <math>x^2 + y^2</math>. Such a function is commonly written as <math>f(x, y)=x^2 + y^2</math> and referred to as "a function of two variables". Likewise one can have a function of three or more variables, with notations such as <math>f(w,x, y)</math>, <math>f(w,x, y, z)</math>.