Page 57 - Math Course 1 (Book 2)

Relations as a Function

Mo. 8

Lesson 6 Key Concept

KEY CONCEPTS: Function
1. Determine whether a relation is a function.
2. Find functional values. A function is a relation in which each element of
the domain is paired with exactly one element of
the range.

MO. 8 - L6a

Determine If a Relation Let’s Begin
is a Function

Identify Functions
Vocabulary A-Z
Let us learn some vocabulary Example

A. Determine whether the relation is a function.
Explain.
function
relations in which each element of the domain is x y
paired with exactly one element of the range are
called functions. –2 –8
0 0
x y
2 8
–2 –8
4 16
0 0
This is a function because the
2 8 mapping shows each element of
Answer
4 16 the domain paired with exactly
one member of the range.

vertical line test B. Determine whether the relation is a function.
If a vertical line can be drawn that intersects the Explain.
graph no more than once, then the graph is a x y
function. If a vertical line can be drawn so that it –7 –12
intersects the graph at two or more points, the
graph is not a function. –4 –9
2 –3
Function Not a Function 5 0
y y

0 0 This table represents a function
because the table shows each
x x Answer element of the domain paired
with exactly one element of the
range.
Function
y

0 Vertical
x Line

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