1. Warm Up - Simplify
1) )
3) )

2. Homework Check – 5.4

3. Things to remember…. All arithmetic sequences are LINEAR FUNCTIONS
All geometric functions are EXPONENTIONAL FUNCTIONS
Arithmetic sequences have a common difference
Geometric sequences have a common ratio

4. Exponential Functions
An exponential function is a function with the general form
y = abx
a ≠ 0 and b > 0, and b ≠ 1

5. y = abx
A is the starting value B is growth factor X is time Y is the amount after time

6. Starting Value and Growth Factor
Identify each starting value and the growth factor.
Y= 3(1/4)x
Y= .5(3)x
Y = (.85)x

7. Modeling Exponential Functions
1) Suppose 20 rabbits are taken to an island. The rabbit population then triples every year. The function f(x) = 20 • 3x where x is the number of years, models this situation. What does “20” represent in this problem? What does the 3 represent? How many rabbits would there be after 2 years?

8. 2) Suppose a Zombie virus has infected 20 people at our school
2) Suppose a Zombie virus has infected 20 people at our school. The number of zombies doubles every day.
a) Write an equation that models this.
b) How many zombies are there after 5 days?
c) If there are 1800 students at Knightdale, how long will it take for the Zombie virus to infect the whole school?

9. 3) A Bacteria culture doubles in size every hour
3) A Bacteria culture doubles in size every hour. The culture starts at 150 cells. a) Write an equation to model this. b) How many will there be after 24 hours? c) After 72 hours?

10. 4) A population of 2500 triples in size every year
4) A population of 2500 triples in size every year. a) Write an explicit equation to model this. b) What will the population be in 30 years?

11. Class work
Complete the bacteria handout in your groups.

12. Coming up…
HW tonight – 5.5 HW Stamp Sheets will be collected Friday Quiz 5.2 Friday!