Texas Instruments TI-89, TI-92

Chapter 12: Additional Graphing Topics 205

12ADDLGR.DOC TI-89/TI-92 Plus: Additional Graphing Tools (English) Susan Gullord Revised: 02/23/01 1:03 PM Printed: 02/23/01 2:15 PM Page 205 of 20

The Graph command lets you graph an expression from the Home

screen without using the Y= Editor. Unlike the Y= Editor, Graph lets

you specify an expression in terms of any independent variable,

regardless of the current graphing mode.

If the expression is in

terms of: Use the Graph command

as shown in this example:

The native

independent variable graph 1.25xùcos(x)

non-native

independent variable graph 1.25aùcos(a),a

Graph does not work with sequence graphs or differential equations.

For parametric, polar, and 3D graphs, use the following variations.

In PARAMETRIC graphing mode: Graph xExpr, yExpr, t

In POLAR graphing mode: Graph expr,

In 3D graphing mode: Graph expr, x, y

Graph does not copy the expression to the Y= Editor. Instead, it

temporarily suspends any functions selected on the Y= Editor. You

can trace, zoom, or show and edit Graph expressions on the Table

screen, just the same as Y= Editor functions.

Each time you execute Graph, the new expression is added to the

existing ones. To clear the graphs:

¦ Execute the ClrGraph command (available from the Home

screen’s † Other toolbar menu).

— or —

¦ Display the Y= Editor. The next time you display the Graph

screen, it will use the functions selected on the Y= Editor.

You can define a user-defined function in terms of any independent

variable. For example:

define f1(aa)=1.25aaùcos(aa)

graph f1(x)

and:

define f1(aa)=1.25aaùcos(aa)

f1(x)!y1(x)

Graphing Directly

from the Home

Screen

Note: Graph uses the

current Window variable

settings.

Tip: Graph is available from

the Home screen’s

†

toolbar menu.

Tip: To create a table from

the Home screen, use the

Table command. It is similar

to Graph. Both share the

same expressions.

Clearing the Graph

Screen

Extra Benefits of

User-Defined

Functions

For function graphing,

x is the native variable.

Specify the independent

variable; otherwise, you

may get an error.

Defined in terms of “aa”.

Refers to the function by using the

native independent variable.