Page 66 - Math Course 3 (Book 1)

Exponential Functions
Mo. 2

Lesson 5 Let’s Begin

KEY CONCEPTS:
1. Graph exponential functions. Graph an Exponential Function with a > 1
2. Use exponential functions to solve problems.
3. Identify data that displays exponential Examples
behavior.

Graph y = 3 . State the y-intercept.
x
MO. 2 - L5a
Graph the ordered pairs and connect the points
Graphing Exponential with a smooth curve.
Functions

x
Vocabulary A-Z x 4 –1 y 1
Let us learn some vocabulary –1 3 16
0 3 0 1
1 3 1 3
2 3 2 9 y = 3 x
exponential function

x
y = 2 is in the class of functions called
exponential functions where the variable
is the exponent. Answer The y-intercept is 1.

This function is neither linear nor quadratic.

x
Graph y = 4 . State Use the graph to determine the approximate value
1.5
the y–intercept of 3 .
x 4 x y The graph represents all real values of x and their
x
1
–2 4 –2 16 corresponding values of y for y = 3 .
–1 4 –1 1 Answer The value of y is about 5 when
4
0 4 0 1 x = 1.5

1 4 1 4 1.5
2 4 2 16 Use a calculator to confirm this value. 3 ≈ 5.196
3 4 3 64

Graph Exponential Functions with 0 < a < 1

Key Concept Examples

1 x
Exponential Function Graph y = . State the y-intercept
4
An exponential function is a function that can be Graph the ordered pairs and connect the points
with a smooth curve.
x
described by an equation of the y = a , where a > 0
and a ≠ 1.
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