View Full Version : Domain and Range Question

09-28-2008, 03:22 PM
I am given a chart with month on the x axis and temperatures on the y axis. It is a belll shaped relation and i am supposed to find the domain, and range of the data. the whole concept confuses me as to how i get both of these. any help?

09-28-2008, 04:42 PM
Hello there:

What you've described sounds more like a GRAPH because charts do not have axes.

A CHART is an array of data, arranged in rows and columns.

I'm going to assume that you have at least looked up the definitions for the terms "domain" and "range", and that you understand these definitions. If your confusion is that you do not actually understand the definitions, then please check the following web page, and return here with your specific question(s) about the definitions.

One of Thousands of Internet Resources on DOMAIN and RANGE (http://www.purplemath.com/modules/fcns2.htm)

The answer to this exercise depends upon the graph. Is the bell-shaped relationship shown as a curved line or a number of discrete points?

If you can see individual points, then the domain is the set of all the x-coordinates, and the range is the set of all the y-coordinates.

If you see a curved line, then there are an infinite number of points that comprise the graph. In this case, you will need to express both the domain and range in terms of intervals using set notation, interval notation, or whatever notation you may have learned.

For example, if we look at the relationship between x and y defined as y = x^2 + 1, AND we restrict our interest to the part of the parabola that runs from x = -4 through x = 4, then we would state the restricted domain and range as follows.

Domain: [-4, 4], or Domain: -4 ? x ? 4

Range: [1, 17], or Range: 1 ? y ? 17

And if we have discrete points (instead of a portion of a parabola) on such a graph, then we explicitly write out all of the elements in the domain and range. (If these points all have integer coordinates, then the following applies.)

Domain: {-4, -3, -2, -1, 0, 1, 2, 3, 4}

Range: {1, 2, 5, 10, 17}

If you need more help, then please show whatever work or reasoning that you've been able to do so far.


~ Mark :)