Answer:
Relations are sets of ordered pairs. Usually, the first coordinates come from a set called the domain and are thought of as inputs. The second coordinates are thought of as outputs and come from a set called the range (I actually prefer to call this the co-domain but that’s a long story we don’t need to go into here).
In order for a relation to be a function, each input must have one and only one output.
CARRY ON LEARNING
