4 2 Exponential Functions An exponential function is

4. 2 Exponential Functions

An exponential function is a function of the form where a is a positive real number (a > 0) and. The domain of f is the set of all real numbers.

Summary of the characteristics of the graph of a >1 • The domain is all real numbers. Range is set of positive numbers. • No x-intercepts; y-intercept is 1. • The x-axis (y=0) is a horizontal asymptote as a>1, is an increasing function and is one • to-one. • The graph contains the points (0, 1); (1, a), and (-1, 1/a). • The graph is smooth continuous with no corners or gaps.

Summary of the characteristics of the graph of 0 <a <1 • The domain is all real numbers. Range is set of positive numbers. • No x-intercepts; y-intercept is 1. • The x-axis (y=0) is a horizontal asymptote as 0<a<1, is a decreasing function and is one-to-one. • The graph contains the points (0, 1); (1, a), and (-1, 1/a). • The graph is smooth continuous with no corners or gaps. •

(-1, 5) (0, 3) y=2

Domain: All real numbers Range: { y | y >2 } or Horizontal Asymptote: y = 2

The number e is defined as the number that the expression In calculus this expression is expressed using limit notation as

Exponential Equations

Solve: