what can be a function
In mathematics, a function is a relation between a set of inputs and a set of permissible outputs with the property that each input is related to exactly one output. An example is the function that relates each real number x to its square x 2.n inverse function for f, denoted by f â1, is a function in the opposite direction, from Y to X, satisfying. That is, the two possible compositions of f and f â1 need to be the respective identity maps of X and Y.