1. 8-1: Exponential Growth day 2 Objective CA 12: Students know the laws of fractional exponents, understanding exponential functions, and use these functions in problems involving exponential growth and decay.

2. Using Exponential Growth Models When a real-life quantity increases by a fixed percent each year (or other time period) the amount y of the quantity after t years can be modeled by Where a is the initial amount, and r is the percent increase expressed as decimal. The quantity 1+r is called the growth factor

3. Example 3: Modeling Exponential Growth In 1980 about 2,180,000 US workers worked at home. During the next ten years, the number of workers working at home increased by 5% per year. Write a Model giving the number of w (in millions) of workers working at home t years after 1930

5. Graph the model Use the graph to estimate the year when there were about 3.22 million workers who worked at home.

6. Compound Interest Consider the initial principal P deposited in an account that pays interest at an annual rate r (expressed as a decimal), compounded n times per year. The amount A in the account after t years can be modeled by this equation:

7. Example 4: Finding the Balance of an Account You deposit $1500 in an account that pays 6% annually. Find the balance of the account after 1 year if the interest is compounded: annually, semiannually, quarterly

10. 8 – 1 day 2 Home work page 469 43 – 48, 55, 62 –70