How (Function Machine)

Function Machine Help

How Do I Use This Activity?

This activity allows the user to explore simple linear functions; the function is determined by looking for patterns in the outputs. The functions available for exploration in the function machine activity have one of the following forms:

y = x * a

y = x + a

y = x - a

where a can be any integer between -10 and 10.

Note that in this applet the variable y is used instead of the notation f(x).

This Java applet requires a Java-capable browser. If you don't see the applet Java may not be functional in your browser or on your machine.

Controls and Output

To find out what the machine will do with a number:
- Type the number into the X= [____] space (in our example, number 5 is typed in)
- Press the Enter button:
- Observe the resulting number in the Y= [____] window (in our example, number 7 is the result):
- You can input as many numbers as you need to find the rule
To check if you guessed the rule right, select an operation and type a number in the Y = X [?] [____] space, and then press the Check formula button:
- To select an operation, click on the selection sign next to the question mark. You will see three operations (and a question mark):
- Click on the operation you want to select, and it will appear instead of the question mark (in our example, + is selected):
- Type the number that completes the rule in the space after the sign (in our example, 2 is typed):
- Click on the Check formula button:
- You will see one of the two messages under the picture of the machine: either Correct answer! or Try again!
To set a new function machine (that is, a new rule), click once on the Set new function button: