Question

Given the relation `{(8,2), (3,6), (7,5), (k,4)}`, which value of `k` will result in the relation not being a function?

Answer 1

If `color(blue)(k in {8,3,7})` then the given set of pairs is not a function.

Explanation:

A set of pairs represents a mapping of the first value of the pair unto the second value.

To be a function no mapping in the set can map the same value unto more than one value.

For example, if `k=7` in the given set,
then `color(white)("XXX")7 rarr 5` because of the pair `(7,5)`
and `color(white)(".XXX")7 rarr 4` because of the pair `(k=7,4)`
`rArr` this would not be a function.