CHAPTER 4 Calculator Notes for the TI-89, TI-92 Plus, and Voyage ...

Note 4F • Graphing Absolute-Value Functions
To use the absolute-value function, press 2nd [MATH] 1:Number 2:abs(. For
example, to graph y ⏐x 3⏐ enter y1abs(x3) into the Y Editor screen,
set an appropriate window, and press ♦ [GRAPH].
Note 4G • Boolean Expressions
[15.8, 15.8, 1, 7.6, 7.6, 1]
You can use Boolean expressions to define a piecewise function. Boolean
expressions are statements using , , , , , or that are either true
or false. To find these symbols, press [MATH] 8:Test. (You can also
press [] or [].)
As an example of a piecewise function, on the Y Editor screen enter
y1when(x1,2x2 2nd
2nd
2nd
,0). Get the when( command from the catalog, or type it.
The when( command requires three parameters: first the Boolean expression,
second the value when the expression is true, and third the value when the
expression is false. You can evaluate the function for particular values of x
on the Home screen and it can be graphed.
[15.8, 15.8, 1, 7.6, 7.6, 1]
By nesting when( commands, you can link any number of functions together
in a piecewise fashion.
[15.8, 15.8, 1, 7.6, 7.6, 1]
With repeated nesting you can also limit the domain by designating
undefined x-values. Enter this equation into the Y Editor screen:
y1when(x3,when(x1,when(x2,undef,2x2 ),4x),undef). The graph
is undefined for x-values less than 3 and x-values greater than 2.
TI-89/TI-92 Plus/Voyage 200
(continued)
38 CHAPTER 4 Discovering Advanced Algebra Calculator Notes for the Texas Instruments TI-89, TI-92 Plus, and Voyage 200
©2004 Key Curriculum Press