1. Section 16.1
Functions

2. Functions
Identify functions.

3. Identifying Functions
A function is a set of ordered pairs that assigns to each x-value exactly one y-value.

4. Function Analogy Domain: Critters on the Bus Range: Color of Bus Stop
(monkey, red)
(puppy, yellow)
(kitty, green)
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5. Function Analogy Domain: Critters on the Bus Range: Color of Bus Stop
In a function, x-values cannot repeat.
NOT A FUNCTION
(monkey, red)
(puppy, yellow)
The monkey can’t get off at two different stops.
Where’d the extra monkey come from??
(monkey, green)
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6. Function Analogy Domain: Critters on the Bus Range: Color of Bus Stop
In a function, y-values can repeat.
FUNCTION
(monkey, red)
(puppy, yellow)
(kitty, yellow)
Can two critters get off at the same stop?
Yes!

7. Identifying Functions
A function is a set of ordered pairs that assigns to each x-value exactly one y-value.
For each input there is only one output.
All x-coordinates must be different.
The y-coordinates can be repeating.
Determine if the relation is also a function.
{(2, 5), (-3, 7), (4, 5), (0, -1)}
{(1, 4), (6, 6), (1, -3), (7, 5)}
yes no