Relations & Functions

• Ordered Pairs

• Table

• Graph

• Mapping Diagram

A function is a relation in which each input(domain - x) is paired with exactly one output(range -y)
x's Do Not Repeat

Which relation represents y as a function of x?

Which relation does not represent y as a function of x?

• Domain

• {-2, 0, 4, 5}

• Range

• {2, 5, 6}

• Is the relation a function?

• Yes; the x's DO NOT repeat

• Domain

• {-1, 2, 4}

• Range

• {3, 6, 8}

• Is the relation a function?

• No; the x value of -1 repeats

Take a look at the 2 mapping diagrams on the next slide. Decide which mapping is a function and why.

A mapping is a function if there is only ONE ARROW coming out of each DOMAIN value. In the previous slide, Mapping #1 is a function and Mapping #2 is NOT a function.

x's DO NOT repeat

Take a look at the 2 graphs on the next slide. Decide which graph is a function and why.

• If a vertical line can be drawn on the graph that intersects the graph more than once, the graph DOES NOT represent a Function.

• Easy Reference

• Displays the Input