Question

How do you find the domain and range and determine whether the relation is a function given {(4,5), (6,5), (3,5)}?

Answer 1

See explanation.

Explanation:

If a relation is given as the set of points then:

• the domain is the set of all first (`x`) coordinates of the points. Here we have: `D={3,4,6}`

• the range is the set of all second (`y`) coordinates. Here there is only one value of `y`, so rangeis a one element set: `R={2}`

• to find if a relation is a function you have to find out if all values in the domain occur only once (have only one value)

Here the condition is met, so it is a function.

If there was another value for any of already mentioned arguments (for example if a point `(3,-1)` was added) then such relation would not be a function because argument `3` would have `2` different values: `5` and `-1`