1'8 An Introduction to Functions

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1.8 An Introduction to Functions

• Goal Use four different ways to represent a
  function.

2
Function - A rule that describes a dependent
relationship between two quantities.
Domain - The set of input values in a function.
Range - The set of output values in a function.
3
Model
Let p the perimeter of each figure
Let n of triangles
Table
Graph
Equation
p
Dependent
p
n
p n 2
8 7 6 5 4 3 2 1
1
3
Dependent
2
4
perimeter
3
5
Line is discrete
4
6
5
7
n
0 1 2 3 4 5 6 7
of triangles
6
8
4
Let n of triangles
Let p the perimeter of each figure
Equation
Graph
Table
p n 2
1
2
3
p
p
n
8 7 6 5 4 3 2 1
p 3
p 4
p 5
1
3
2
4
perimeter
input
3
5
output
4
6
n
0 1 2 3 4 5 6 7
5
7
of triangles
6
8
5
Let n of triangles
Let p the perimeter of each figure
Equation
Graph
Table
p n 2
p
p
n
8 7 6 5 4 3 2 1
1
3
2
4
perimeter
Domain
3
5
Range
4
6
n
0 1 2 3 4 5 6 7
5
7
of triangles
6
8
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What is a function?
A function is a rule that ensures there is
exactly one output for every input.
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Is it a function?
No, there are two output for one input.
Yes, there is exactly one output for every input.