Texas Instruments TI-89 Titanium User Manual

Symbolic Manipulation 224
Determining If a Variable Is Undefined
• If x is defined, the result may be in a form
you did not expect.
Note: When defining a variable, it’s a good
practice to use more than one character
in the name. Leave one-character names
undefined for symbolic calculations.
Method: Example:
Enter the variable name.
Use the
getType function.
Unless you knew that
5 had been stored to
x previously, the
answer 75 could be
misleading.
If defined, the variable’s
value is displayed.
If undefined, the variable
name is displayed.
If defined, the variable’s
type is displayed.
If undefined, “
NONE” is
displayed.

Texas Instruments TI-89 Titanium Specifications

General

Display Type	LCD
Display Resolution	160 x 100 pixels
CPU	Motorola 68000
CPU Speed	16 MHz
RAM	256 KB
Flash ROM	2.7 MB
Programming Language	TI-BASIC, Assembly
Power Source	4 AAA batteries
Connectivity	I/O port
Dimensions	7.5 x 3.5 x 1 inches