2. Objectives:  Understand the exponential growth/decay function family.  Graph exponential growth/decay functions.  Use exponential function to models in real life. Vocabulary: exponential function, rule of 72, exponential growth, exponential decay

3. base b increasing decreasing

4. The variations of exponential functions are practical in a wide variety of application problems. The most widely used are: Growth:y = a (1 + r ) t Decay:y = a (1 – r ) t Note: the rate r is measured the same time period as t, where a stands for the initial amount. 5.3 Exponential Functions

5. You purchase a baseball card for $54. If it increases each year by 5%, write an exponential growth model. How much will the card be worth in 18 months? 5.3 Exponential Functions

6. You have a new computer for $2100. The value of the computer decreases by about 30% annually. When the computer will be worth $500? 5.3 Exponential Functions

8. How long does it take to double an investment that grows at the rate of: 9% per year? 6% per month?

9. The half-life of a radioactive isotope is 5 days. At what rate does the substance decay each day? Not technically growth or decay because no rate, but close. Need to FIND rate.