Texas Instruments PLUS TI-89 - Manual (Page 77)

60 Chapter 3: Symbolic Manipulation
03SYMBOL.DOC TI-89/TI-92 Plus: Symbolic Manipulation (English) Susan Gullord Revised: 02/23/01 10:52 AM Printed: 02/23/01 2:12 PM Page 60 of 24
You can “undefine” a defined variable by deleting it.
To delete: Do this:
One or more specified
variables Use the DelVar function.
You can also delete variables by using the
VAR-LINK screen ( 2 °) as
described in Chapter 21.
All one-letter variables
(
a – z ) in the current
folder
From the Home screen Clean Up menu,
select 1: Clear a - z . You will be prompted to
press ¸ to confirm the deletion.
By using the “with” operator ( | ), you can:
¦ Temporarily override
a variable’s defined
value.
¦ Temporarily define a
value for an undefined
variable.
To type the “with” operator ( | ), press:
TI . 89: Í
TI . 92 Plus: 2 Í
Deleting a Defined
Variable
Note: For information about
folders, refer to Chapter 5.
Temporarily
Overriding a
Variable
Note: For more information
about the | operator, refer to
page 67.