1. Average Rate of Change

2. Rate of Change
A ratio that describes how one quantity changes as another quantity changes
Slope can be used to describe it

3. Rate of Change Positive – increases over time
Negative – decreases over time
Zero- doesn’t change over time
Horizontal movement
Undefined - vertical movement

4. Rate of Change
Linear functions have a constant rate of change, meaning values increase or decrease at the SAME rate over a period of time

5. Average Rate of Change using function notation

6. Ex 1 Find the Average Rate of Change
f(x) = 2x2 – 3 from [2, 4].

7. Ex 2 Find the Average Rate of Change
f(x) = -4x + 10 from [-1, 3].
m = -4

8. A. Find the rate of change from day 1 to 2.
Ex 3 Find the Average Rate of Change
A. Find the rate of change from day 1 to 2.
m = 11
Days (x)
Amount of Bacteria f(x) 1 19 2 30 3 48 4 76 5
121 6
192
B. Find the rate of change from day 2 to 5.

9. Ex 4 Find the Average Rate of Change Households in Millions f(x)
In 2008, about 66 million U.S. households had both landline phones & cell phones. Find the rate of change from 2008 – 2011.
Year (x)
Households in Millions f(x)
2008 66
2009 61
2010 56
2011 51
m = -5
What does this mean?
It decreased 5 million households per year from 2008 – 11.