Math 10C
Relations & Functions Lesson #6
Functions
Objective: By the end of this lesson you will be able to:
- Describe the difference between a function and a relation that is not a function
- Determine whether a relation is a function by looking at its mapping diagram, table of
values, set of ordered pairs, or graph
Warm-Up:



Complete the mapping diagram for each of the following functions with domain {1, 4, 9, 16}
and range {1, 2, 3, 4}.
i) The output is the square root of the input
ii) The output is a factor of the input
input
output
input
output
1
1
1
1
4
2
4
2
9
3
9
3
16
4
16
4
List the set of ordered pairs for each relation.
i)
ii)
Plot the points of each relation on a Cartesian plane.
i)
ii)
A function is a special type of relation in which each input value _________________________
__________________________ (i.e. each element in the domain is related to exactly _________
element of the range.)
e.g. 1) Which of the relations in the Warm-Up is a function? Explain.
Math 10C
Relations & Functions Lesson #6
* Every ______________ is a ______________, but not every ______________ is a
______________.
Explain how you can tell whether a relation is a function by looking at:
a) The mapping diagram
b) A list of ordered pairs
c) A table of values
d) The graph
Vertical Line Test

e) An equation
e.g. 2) Identify whether each relation is a function.
a) {(0, 1), (4, 2), (-7, 3), (4, -1)}
b)
c)
Assignment:
x
-2
-1
0
1
2
y
3
-3
-5
-3
3
Functions Practice Assignment
d) y  8  2 x