A mapping diagram is a visual representation of a function that shows how the elements of the domain are paired with the elements of the range. It consists of two parallel columns, with the first column representing the domain of a function and the other column representing its range. Lines or arrows are drawn from the domain to the range to represent the relation between any two elements. A function represented by the mapping in which each element of the range is paired with exactly one element of the domain is called a one-to-one mapping. If one element in the domain is mapped with more than one element in the range, the mapping is called a one-to-many relation, which is not a function. Conversely, if the element(s) in the range that have mapped more than one element in the domain, the mapping is called a many-to-one mapping.

To create a mapping diagram, two columns are created, one for the domain and the other for the range. Every input value (domain) is listed in one column, and every output value (range) is listed in the other column. Then, an arrow connects each input value to its corresponding output value. The image below shows a mapping diagram for the given function:

Mapping Diagram Example

Mapping diagrams are used to show relationships and functions. They are helpful in identifying whether a relation is a function or not.