Texas Instruments TI-89 Guide Book

Chapter 3: Symbolic Manipulation 67
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 67 of 24
To type the “with” operator (
|
), press:
TI
.
89:
Í
TI
.
92 Plus:
2 Í
For every occurrence of a
specified variable, you can
substitute a numeric value or an
expression.
To substitute for multiple
v
ariables at the same time, use
the Boolean
and
operator.
For every occurrence of a simple
expression, you can substitute a
v
ariable, numeric value, or
another expression.
By replacing a commonly used
(or long) term, you can display
results in a more compact form.
You can substitute complex
v
alues just as you would for other
v
alues.
All undefined variables are treated as real numbers in symbolic
calculations. To perform complex symbolic analysis, you must define
a complex variable. For example:
x+yi
!
z
Then you can use
z
as a complex variable. You can also use z_. For
more information see the _ (underscore) topic in Appendix A.
Substituting Values and Setting Constraints
The “with” operator (
|
) lets you temporarily substitute values
into an expression or specify domain constraints.
Typing the “With”
Operator
Substituting for a
Variable
Substituting for a
Simple Expression
Note:
acos(x)
is different
from
a*cos(x)
.
Substituting
Complex Values
Note: For an overview of
complex numbers, refer to
Appendix B.
Tip: To get the complex
i
,
press
2)
.
Do not simply
type the letter i on the
keyboard.
First derivative of x
ìò
at x = 5
Substituting s for sin(x) shows that
the expression is a polynomial in
terms of sin(x).

Texas Instruments TI-89 Specifications

General

Display size (HxV)	100 x 160 mm
Memory type	639K FLASH ROM, 188K bytes RAM
Compatible operating systems	Operating System 2.09
Battery type	AAA