How to Use a Table to Graph Functions
One of the easiest ways to graph functions is to use a table. By choosing the values you put into the function, you can get a nice set of values to graph on your Cartesian plane. However, you will have to choose your values carefully, because getting numbers that are too high or are fractions can make it a little bit more of a challenge. If you are just beginning to learn to graph functions, using a table can be a fun and fairly simple way to start.
Other People Are Reading
Instructions
-
-
1
Start by drawing a simple table with two vertical columns. Label the first column "x" and the second column with the function, such as "y = 2x + 2."
-
2
Choose at least three values for x and write them in the chart. It is a good idea to choose 0, a positive number like 2 and a negative number like -3. This will help you get a straight line.
-
-
3
Put your chosen x values into the function. You will get three values for y. When you put in 0 for x in this example, y = 2. When you put in 2 for x in this example, y = 6. When you put in -3 for x in this example, y = -4.
-
4
Write these values in the column that is marked "y = 2x + 2." You now have three ordered pairs, (0,2), (2,6) and (-3,-4).
-
5
Draw your Cartesian plane on the graph paper. Make sure it is large enough to house all of the values in your three ordered pairs.
-
6
Plot the three points. They should make a straight line, because you are graphing a linear function. Connect the dots with a straightedge, making sure to continue the line past the points you have plotted. Put an arrow on the end of the line to show that it extends infinitely in both directions.
-
1
Tips & Warnings
If you do not get a straight line, make sure you are graphing a linear function. If you are, you did the math wrong.
If you get a fraction or a very large number, consider choosing a different value for x. It will be hard to graph these points.
Always choose three values, as this is the only way you can be sure you have the line right. Two points are not enough to make an accurate line.
