Problem:
Given the family of functions

f(x) = |2a - x|

with parameter a, draw the graphs for the parameters a  =  0, 1, ..., 4.

Visualization:
Using Twiddle (from the University of Arizona):

1. After starting up the program, you are prompted "Would you like some instructions?" Use the arrow keys to move to either Yes or No and then press .
2. If you choose Yes then read the instructions and press when you are ready to proceed.
3. Use the arrow keys to highlight Function Ops and press .
4. Use the arrow keys to highlight Create Function and press .
5. At the prompt, f(x) =, type
abs(2*a-x) .
6. At the prompt, Initial a : 1, type 0 .
7. At the prompt, Minimum x : -10, press .
8. At the prompt, Maximum x : 10, press .
9. At the prompt, Minimum y : -10, press .
10. At the prompt, Maximum y : 10, press .
11. Use the arrow keys to move to Plot Function and press .
12. You will now see the graph of the function when a = 0. Each time that you type uppercase the value of a will be increased by one and the associated function plotted. By typing lowercase you will decrease a by one.