Question

difference between a function and a relation

Answer 1

A function is a special kind of relation. Relations pair up x and y coordinates, either by listing them (explicitly) or by writing an equation (implicitly). Functions have the additional property that no two values of y have the same value of x. Put another way, if you view x as the input and y as the output, functions have the property that each input yields only one output.

Answer 2

A relation is any set of ordered pairs.

For example, {(5,9), (1,2), (8,11), (10,20), (4,7)}

A function is a special type of relation where each x-coordinate has exactly 1 y-coordinate.