Relations and Functions

•The first elements in the ordered pairs (the x-values), form the domain. The second elements in the ordered pairs (the y-values), form the range. The range is the dependent variable.

Example: (9,2)

Function: A function is a set of ordered pairs in which each x-element has only ONE y-element associated with it.

If it intersects in one point it’s a function.If more then it’s not a function.

Graph

Functions in real life:

how fastThe car travels

Writing Functions

x

Y

1

-2

2

-1

3

0

4

1

1-3=-2 or 1(-2)=-2

Which relations below are functions? Relation #1 { (-1,2), (-4,51), (1,2), (8,-51) }Relation #2 { (13,14), (13,5) , (16,7), (18,13) }Relation #3 { (3,90), (4,54), (6,71), (8,90) }

Which relations below are functions? Relation #1 { (3,4), (4,5), (6,7), (8,9) }Relation #2 { (3,4), (4,5), (6,7), (3,9) }Relation #3 { (-3,4), (4,-5), (0,0), (8,9) }Relation #4 { (8, 11), (34,5), (6,17), (8,19) }

Group 1

Group 2

Given f (x) = 3x + 7, find f (5).

Choose:15 22 42D

D

DD

DD

Speed Question

 

Use functional notation to describe the function displayed at the right.

x y-3 9-2 4-1 10 01 12 43 9

Speed Question

Choose:f (x) = 2xf (x) = x² f (x) = x + 2

DDDDDDDDD

Larry's father has five sons named Ten, Twenty, Thirty, Forty...Guess what would be the name of the fifth???

A challenge question

Thank you