## Precalculus (6th Edition) Blitzer

The relation is not a function. Domain: $\left\{3, 4\right\}$ Range: $\left\{4, 5\right\}$
RECALL: (i) A function is a relation where every first coordinate is paired with exactly one second coordinate. (ii) The domain of a relation is a set that contains all the first coordinates. (iii) The range of a relation is a set that contains all the second coordinates. Note that the first coordinates $3$ and $4$ are paired with two different second coordinates. Thus, the given relation is NOT a function. The domain of the relation is $\left\{3, 4\right\}$. The range of the relation is $\left\{4, 5\right\}$.