Question

Dose this tablet represent a function? Why or why not? {(2,1), (2,4), (3,4), (4,2), (5,5)}

Answer 1

This mapping isn't a function.

Explanation:

A mapping specifies a relation between two sets of items (input and output). For example, a mapping of the form
`\lbrace (x_(0),\, y_(0)),\, (x_(1),\, y_(1))\rbrace` would map the input
`x_(0)` to output
`y_(0)` and map the input
`x_(1)` to output
`y_(1)`.

A function is a mapping where each input is associated with exactly one output.

Note that both
`(2,\, 1)` and
`(2,\, 4)` are in the mapping given in this question. The input
`2` is mapped to more than one outputs. Thus, this mapping isn't a function.