Transcript 4.6 – Formalizing Relations and Functions

4.6 – Formalizing Relations
and Functions
Vocab, Vocab, Vocab!!
1. Relation – a pairing of numbers in one
set with numbers in another set.
2. Domain – the set of x-values of a relation
3. Range – the set of y-values of a relation
Identify the domain and range of each
relation. Represent the relation with a
mapping diagram. Is the relation a function?
{(-2, 0.5), (0, 2.5), (4, 6.5), (5,2.5)}
DOMAIN: {-2, 0, 4, 5}
RANGE: {0.5, 2.5, 6.5}
Domain
-2
Yes, the relation is a
function because each
domain value is
mapped to one range
value.
0
4
5
Range
0.5
2.5
6.5
Identify the domain and range of each
relation. Represent the relation with a
mapping diagram. Is the relation a function?
{(6, 5), (4, 3), (6, 4), (5, 8)}
DOMAIN: {4, 5, 6}
RANGE: {3, 4, 5, 8}
Domain
4
5
No, the relation is not
a function because the
domain value 6 is
mapped to two range
values.
6
Range
3
4
5
8
And more vocab!
4. Vertical Line Test – another way to decide
if a relation is a function.
If a vertical line crosses a graph only
once, then the relation is a function
If a vertical line crosses a graph more
than once, then the relation is not a
function.
Are the following relations
functions? Use the vertical line test.
Just one more vocab word!
5. Function Notation: replacing y with f(x) in
an equation that represents a function.
Example: f(x) = -3x + 1
Find the range for each function for
the given domain.
1. f(x) = 5x – 2; {-1, 3, 10}
2. f(x) = |x – 2|; {-3, 0, 4}
Homework
Page 272 # 8 – 15, 18 – 21, 24 - 25