test

Page 1

APPENDIX I

Section A Exponential Functions

A-1

Exponential and Logarithmic Functions APPENDIX OUTLINE A

Exponential Functions A-1

B

Logarithms and Logarithmic Functions A-13

C

Properties of Logarithms; Solving Exponential/Logarithmic Equations A-28

D

Applications from Business, Finance, and Science A-44

A Exponential Functions Learning Objectives In Section A you will learn how to:

A. Evaluate an

Demographics is the statistical study of human populations. In this section, we introduce the family of exponential functions, which are widely used to model population growth or decline with additional applications in science, engineering, and many other ďŹ elds. As with other functions, we begin with a study of the graph and its characteristics.

exponential function

B. Graph general exponential functions

C. Graph base-e exponential functions

D. Solve exponential equations and applications

A. Evaluating Exponential Functions In the boomtowns of the old west, it was not uncommon for a town to double in size every year (at least for a time) as the lure of gold drew more and more people westward. When this type of growth is modeled using mathematics, exponents play a lead role. Suppose the town of Goldsboro had 1000 residents when gold was ďŹ rst discovered. After 1 yr the population doubled to 2000 residents. The next year it doubled again to 4000, then again to 8000, then to 16,000 and so on. You probably recognize the digits in blue as powers of two (indicating the population is doubling), with each one multiplied by 1000 (the initial population). This suggests we can model the relationship using P1x2 1000 # 2x where P(x) is the population after x yr. Further, we can evaluate this function, called an exponential function, for fractional parts of a year using rational exponents. The population of Goldsboro one-and-a-half years after the gold rush was 3 3 Pa b 1000 # 22 2

1000 # 1 122 3 2828 people

A-1


Turn static files into dynamic content formats.

Create a flipbook
Issuu converts static files into: digital portfolios, online yearbooks, online catalogs, digital photo albums and more. Sign up and create your flipbook.