Warm ups

1. The relation defined by the set of ordered pairs below is not a function. Which pair could be removed to obtain a function??

{(-5,1) (2,3) (1,6) (-5,8) (7,3)}

2. Solve x + 2y = 4 if the domain is {-4,0,4}

Homework Questions?

And Return Quizzes

5-5 Functions

Objective: To find the value of a function for a given element of the

domain.

Standard 16.0

Functional Notation

f(x) Read: “f of x” Means: a function involving x Equals: y

Example 1

Given f(x) = 3x + 2, solve for

f(2) = 3(2) + 2 6 + 2 8

f(w) = 3(w) + 2 3w + 2

Steps:

1.Replace any “x” with the new item inside the parenthesis (plug it in, plug it in!! )

2.Only work with the right side of the equation

Example 1 continued

f(x) = 3x + 2

f(w + 1) = 3(w + 1) + 2 3w + 3 + 2 3w + 5

2f(3) = 2[3(3) + 2] 2(9 + 2) 2(11) 22

Distribute! PEMDAS

Try On Own

g(x) = x – 2x2

g(1) = -1 g(3) = -15

g(-2) = -10

Example 2

h(x) = 4 - 2x

h(1/2) = 4 – 2(1/2) 4 – 1 3

h(w – 3) = 4 – 2(w – 3)4 – 2w + 6 10 – 2w

Example 2 continued

h(x) = 4 - 2x

3h(1) = 3[4-2(1)]3(4 – 2) 3(2) 6

g(3) + 5 = [4 – 2(3)] + 5(4 – 6) + 5 -2 + 5 3

PEMDAS! PEMDAS!

Try On Own

f(x) = 3x2

f(2) = 12 3f(-1) = 9

f(0) = 0 f(-2) = 12

Homework

5-5 Practice