Answer:
In mathematics, a function (f) is a relationship between a given set X (called domain) and another set of elements Y (called codomain) so that each element x of the domain corresponds to a single element f (x) of the domain (the that form the route, also called scope ranking).
See: Relations and functions
In everyday or simpler language, we will say that mathematical functions are equivalent to the common logical process that is expressed as "dependent on."
Mathematical functions can refer to everyday situations, such as: the cost of a phone call that depends on its duration, or the cost of sending a parcel that depends on its weight.
As an example, what would be the rule that relates the numbers on the right with those on the left in the following list ?:
1 --------> 1
2 --------> 4
3 --------> 9
4 --------> 16
The numbers on the right are the squares of those on the left.
The rule is then to "square":
1 --------> 1
2 --------> 4
3 --------> 9
4 --------> 16
x --------> x 2.
To refer to this rule we can use a name, which is usually the letter f (of function). So, f is the rule "square the number".
Usually two notations are used:
x --------> x 2 or f (x) = x 2.
Thus, f (3) means applying the rule f to 3. Doing so results in 3 2 = 9.
Then f (3) = 9. Similarly f (2) = 4, f (4) = 16, f (a) = a 2, etc.
