Question

What is the domain of `{(1,2),(2,6),(3,5),(4,6),(5,2)}`?

Answer 1

Domain is `{1, 2, 3, 4, 5}`

Explanation:

For a collection of discrete pairs `(color(red)(x),color(blue)(f(x))) in {"some collection of ordered pairs"}`

• The Domain is the collection of `color(red)(x)` values
• The Range is the collection of `color(blue)(f(x))` values

`(color(red)(x),color(blue)(f(x))) in {(color(red)(1),color(blue)(2)), (color(red)(2),color(blue)(6)), (color(red)(3),color(blue)(5)), (color(red)(4),color(blue)(6)), (color(red)(5),color(blue)(2))}`

Answer 2

The domain is {1,2,3,4,5}

Explanation:

The domain of a relation or a function is the set of all first elements in an ordered pair that is in the function.

With the usual naming of pairs as `(x,y)`, the domain is the collection (set) of all `x` values.

In notation, the domain of a relation or function `bb"R"` is:

`{x|(EEy)((x,y)in bb"R")}`