Laura Romero Blog #4

 Domain and Range

Hi Class! Today we are going to learn about domain and range.

Domain is the set of all input values of a function. This is the collection of the x-values
Range is the set of all output values of a function. This is the collection of the y-values

In physics, for every action, there is an equal and opposite reaction. In math, for every input, there is an output. Let's look at some examples:

Table A shows the profit generated by a made up company over the course of 5 years.

Year	2009	2010	2011	2012	2013
Profit	10,000	13,000	15,000	18,000	21,000

The years represent the domain, or input, and the profit is the range, or output.

Table B shows a linear function.


The x values of this function represent the domain or input, and the y values represent the range or output.

There are different ways to write domain and range.

Set Builder Notation lists the rules that determine a set that an object is part of, rather than listing the object itself. Ex: D:{x∈ℝl x>0}
Interval Notation. Ex: D: [0,4]

Let's now apply the notations to the previous tables.

Table A
Interval Notation
D: [2009,2013]
 R:[10000,21000]
Set Builder Notation
D{x∈ℝl 2009<x<2013} 
R{y∈ℝl 10000<y<21000}
Table B
Interval Notation 
D: {-∞,∞} 
R: {-∞,∞}
Set builder Notation 
D{x∈ℝl -∞<x<∞} 
R{y∈ℝl -∞<y<∞}

Now you know more about Domain and Range!