1. 1.5 Exponential Functions Monday, August 30, 2004

2. Exponential Functions

3. Rationals and Irrationals

4. Laws of Exponents

5. Applications of Exponents Exponential function occurs very frequently in models of nature and society Examples: population growth, radioactive decay

6. Radioactive Decay Example The half-life of strontium-90 is 25 years. a. If a sample of strontium-90 has a mass of 24 mg, find an expression for the mass m(t) that remains after t years. b. Find the mass remaining after 40 years. c. Estimate the time required for the mass to be reduced to 5 mg.

7. The number e

8. More about e Slope of the tangent line y=2 x m ≈.7 y= 3 x m ≈ 1.1 y=e x m = 1 e ≈ 2.718281828

9. Assignment for Section 1.5 Page 62 – 3, 15, 18,22,26

10. Hand-In Assignment #1 Due Friday, September 3 Page 23: 20, 24, 26, 40, 52 Page A32: 32, 48, 56, 58, 72 Page 62: 16, 20