From MathMotivation.com – Permission Granted For Use and Modification For NonProfit Purposes
Introduction To Functions
A function from the set of xvalues to the set of yvalues is a rule or formula
where x
values are input and the function assigns exactly 1 yvalue to each xvalue that is input.
The set of all xvalues that are input is called the DOMAIN.
The set of all yvalues that correspond to the given xvalues is called the RANGE.
Examples of equations that represent y as a function of x, and some that don’t:
y = 2x + 1
is a function of x
since each xvalue input results in only 1 yvalue.
⏐
y
⏐
=x is NOT a function of x
since x=9 corresponds to both y = 9
and
y = 9.
y = x
2
is a function of x
since each xvalue input results in only 1 yvalue.
y
2
= x is NOT a function of x
since x = 4 results in y = 2
and
y = 2.
y =
±√
x
is NOT a function of x
since x = 4 results in y = 2
and
y = 2.
Function Notation
We may write a formula that defines a function with what is called "function notation".
We replace y with f(x).
We call f(x)
"f
of
x"
and it means
"the y=value when x is input."
Example: If f(x) = 2
x
+ 1, what is
f (
3
), f (
 5
), and f(
A
)?
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
This is the end of the preview.
Sign up
to
access the rest of the document.
 Fall '09
 Crandall
 Anthropology, y= √x

Click to edit the document details