Using the TI-85 graphing calculator, graph the following function
for  x  in the interval  [-1, 4].
[Press here to see animation again!]
The expression above uses two truth functions which are defined as follows:
- If you are not familiar with the graphing of functions on the TI-85,
then first read the
Little's Basic Guide to the TI-85.
- Press the GRAPH key and then pick y(x)=
by pressing the F1 key.
- If necessary, keep pressing F4 key until only
y1= appears on the screen.
- Type in
(x + 1) (x < 2) + (2 - x) (x > 2)
and press the ENTER key.
- You can get the  <  by pressing the 2nd, TEST and then the F4 key.
- The range settings for the graph above is  [-1, 4] × [-3, 3].
The graph above is incorrect; a better approximation to the correct graph is
To obtain this,
- Press the GRAPH key followed by the MORE key.
- Press the F3 key to pick FORMT from the
menu. You will see a menu:
- Use the arrow keys to move to the item DrawDot on the third line
and pres the ENTER key.
- Press F5 to choose GRAPH to get the second
If you want to enter a piecewise defined function with more than two parts as,
for example, the function
3 (x < 2) + (x + 1)(2 < x and x < 5) + (-x)(5 < x)
where the term in the middle contains the function