Determining If A Variable Is Exists - Texas Instruments TITANIUM TI-89 User Manual

• If x is defined, the result may be in a form
you did not expect.
When defining a variable, it's a good
Note:
practice to use more than one character
in the name. Leave one-character names
undefined for symbolic calculations.

Determining If a Variable Is Exists

Determining If a Variable Is Exists Determining If a Variable Is Exists Determining If a Variable Is Exists
Method:
Enter the variable name.
Use the function.
isVar()
Symbolic Manipulation
Unless you knew that
5 had been stored to
x previously, the
answer 75 could be
misleading.
Example:
If defined, the variable's
value is displayed.
If undefined, the variable
name is displayed.
If defined, "true" is
displayed.
If undefined, "false" is
displayed.
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