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 TI-86 graphing calculator:

1. Type in {0,1,2,3,4} STO A
2. Press ENTER key.
3. You can find the symbol "{" by pressing 2nd LIST and F1; the symbol "}" is then obtained by pressing F2.
4. Press the GRAPH key and then pick y(x)= by pressing the F1 key.
5. If necessary, keep pressing the F4 key until all preexisting graphs have been deleted.
6. At the prompt, y1= , type in
7. abs(2 A - x)

8. There are three ways to enter "abs" :
• Press 2nd CATALOG followed by the F1 and the ENTER keys.
• Press 2nd MATH, then F1, and then F5
• Or, you can simply type in "a" "b" "s", but be sure you use lower case lettering.
9. IMPORTANT: "A" in step 7 must be upper case.
10. The WINDOW settings for the graph above are [-10, 10] × [0, 18]:

11. Select GRAPH by pressing F5.
12. Note that the graphs of the functions are plotted in the order in which the values are stored in "A".

Constructed with the help of Chris O'Brien.