# Dr. Byrne Math 112 Fall 2010 ```Dr. Byrne
Fall 2010
Math 112
Domain and Range
domain = set of values of x that are possible to plug into the equation
range = set of values of y that result when you plug in x
Determining the Domain
The domain is all the real numbers (domain = (-∞,∞)) or is restricted – either by context or by
the impossibility of plugging in some values.
There are exactly two reasons why it would be impossible to plug in a value of x:
 you can’t take the square root of a negative number
 you can’t divide by 0
Worksheet 1.2: Determining the Domain of a Function from Its Equation
Find the domain of the function, and describe the domain using interval notation.
8
1. f x   7 x  4
3. f  x   x  4
2. f  x  
x
4.
f x  
2
1  2x
5.
f x   6 x
6.
f x  
x4
Worksheet 1.2: Determining the Domain and Range from a Graph
Describe the domain and range of each graph using interval notation.
(a) domain:
(a) domain:
(a) domain:
(a) domain:
(b) range:
(b) range:
(a) range:
(b) range:
Dr. Byrne
Fall 2010
Math 112
Worksheet 1.2: Determining if a Correspondence is a Function
Determine whether the correspondence is a function (using the definition of a function).
function?
function?
function?
function?
function?
{(3,1),(4,2),(5,1)}
function?
function?
function?
{(2,10),(3,15),(4,20),(3,25)}
Worksheet 1.2: Determining if a Graph is a Function
Determine which of the curves are graphs of functions.
function?
function?
function?
function?
function?
function?
function?
function?
```