structural:reformatting, quality:corruption
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 f can be defined as mapping any pair of real numbers (x, y) {\displaystyle (x,y)} to the sum of their squares, x 2 + y 2 {\displaystyle x^{2}+y^{2}}. Such a function is commonly written as f (x, y) = x 2 + y 2 {\displaystyle f(x,y)=x^{2}+y^{2}} and referred to as "a function of two variables". Likewise one can have a function of three or more variables, with notations such as f (w, x, y) {\displaystyle f(w,x,y)}, f (w, x, y, z) {\displaystyle f(w,x,y,z)}.