91Ó°ÊÓ

• A relation is a function if each element of the domain is paired with exactly one element of the range and a relation is not a function if there exist an element in the domain paired with more than one element of the range.
• The set of input values is known as domain.
• The set of output values is known as Range.

The given relation is $\left\{\left(-2.5,1\right)\text{,}\left(-1,-1\right)\text{,}\left(0,1\right),\left(-1,1\right)\right\}$.

Plot the ordered pairs $\left(-2.5,1\right)\text{,}\left(-1,-1\right)\text{,}\left(0,1\right),\left(-1,1\right)$ on a coordinate plane as shown below:

Input values of the relation are -2.5,-1,0 and the output values are -1,1.

Domain $=\left\{-2.5,-1,0\right\}$

Range $=\left\{-1,1\right\}$

This relation is not a function because -1 in the domain is paired with both -1 and 1 in the range.

Thus, the domain of the given relation is $\left\{-2.5,-1,0\right\}$ and the range is $\left\{-1,1\right\}$. The relation is not a function.