Texas Instruments TITANIUM TI-89 User Manual

Page 270

Symbolic Manipulation

270

For Information about Creating a User-Defined Function

Refer to:

•

“Creating and Evaluating User-Defined Functions” in the Calculator Home Screen
module.

•

“Graphing a Function Defined on the Home Screen” and “Graphing a Piecewise
Defined Function” in the Calculator Home Screen module.

•

“Overview of Entering a Function” in the Programming module.

Undefined Functions

You can use functions such as

f(x)

g(t)

)

, etc., that have not been assigned a

definition. These “undefined” functions yield symbolic results. For example:

Single-Statement Functions

You can use user-defined functions consisting of a single expression. For example:

Use

DelVar

to ensure that

f(x)

and

g(x)

are not

defined.

Then find the derivative of

f(x)

g(x)

with

respect to x.

Note:

To select d from the Calc toolbar menu,

press

… 1 (or press 2 = on the keyboard).