Texas Instruments TI-89 - 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
v
ariables
Use the
DelVar
function.
You can also delete variables by using the
VAR-LINK
screen (
2°
) as
described in Chapter 21.
A
ll 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.