September 19, 2012
1.4 - Graphs of functions
Vertical Line Test – A graph is a function if you can only draw vertical lines that
cross the graph one time.
Which of the following graphs are functions
a)
b)
d)
c)
e)
September 19, 2012
If asked to give the domain and range for a functions, we need to describe
what x's (domain) and y's (range) are a part of the graph.
You can do this with symbols (<, >, <, >) or in words
The domain of this graph is
x's greater than or equal to -6 and
less than or equal to 3
-6 < x < 3
The range of this graph is
y's greater than or equal to -5 and
less than or equal to 2
-5 < y < 2
Note: always set symbols up
lowest <
number or x
<
<
or
<
highest number
Find the domain and range
(1, 6)
(-9, 2)
September 19, 2012
If graph is a function, find:
(a) domain and range
(b) The intercepts, if any
(c) Any symmetry
(2, 7)
(-9, 2)
a) Find f(-1) and f(8)
(10, 6)
b) Is f(-5) positive or negative?
c) For what values of x is f(x) = 0?
(4, -6)
d) For what values of x is f(x) < 0?
September 19, 2012
(2, 7)
e) What are the x-intercepts
(10, 6)
f) What are the y-intercepts
(-9, 2)
g) How often does the line y = 4
intersect the graph?
(4, -6)
h) How often does the line x = -2
intersect the graph?
i) For what values of x does f(x) = 2?
Homework: page 46
9, 11, 12, 13, 14