Texas Instruments TI-83 Plus Silver Edition Manual

10/23/01 © 2000, 2001 Texas Instruments
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Getting Started
Start here
How To…
Start and quit Inequality Graphing
Define an inequality or equation
Shade the inequality intersection or union
Examples
Defining an inequality or equation in the Y= editor
Defining an inequality or equation in the X= editor
Exploring non-linear functions with Pol-trace
More Information
Storing Coordinates Warning Messages
Error Recovery Customer Support


Inequality Graphing for the TI-83 Plus Page 2
Important Information
Texas Instruments makes no warranty, either expressed or
implied, including but not limited to any implied warranties of
merchantability and fitness for a particular purpose, regarding
any programs or book materials and makes such materials
available solely on an “as-is” basis.
In no event shall Texas Instruments be liable to anyone for
special, collateral, incidental, or consequential damages in
connection with or arising out of the purchase or use of these
materials, and the sole and exclusive liability of Texas
Instruments, regardless of the form of action, shall not exceed
the purchase price of this product. Moreover, Texas Instruments
shall not be liable for any claim of any kind whatsoever against
the use of these materials by any other party.
This graphing product application (APP) is licensed. See the
terms of the license agreement.
Copyright © 2000, 2001 Texas Instruments Incorporated.

Inequality Graphing for the TI-83 Plus Page 3
What is Inequality Graphing?
The Inequality Graphing application for the TI-83 Plus gives you
new features for graphing equations and inequalities and
evaluating the relationship between them. Using the Inequality
Graphing application, you can
•enter inequalities using relation symbols
•graph inequalities and shade the union and intersection
regions
•enter inequalities (vertical lines only) in an X=editor
•trace points of interest (such as intersections) between
relations
•store (x,y) coordinate pairs to lists for viewing and optimizing
functions for linear programming
Inequality Graphing is available in two different versions, English
only and international. The international version contains the
English version and also supports Dutch, French, German,
Portuguese, and Spanish. To run Inequality Graphing in a
language other than English, you must have the corresponding
language localization application installed and running on your
calculator. Language localization applications are available for
download free of charge in TI’s online store at epsstore.ti.com.

Inequality Graphing for the TI-83 Plus Page 4
Where to Find Installation Instructions
You can find detailed instructions on installing Flash applications
at education.ti.com/guides.

Inequality Graphing for the TI-83 Plus Page 5
Getting Started
Getting Started is a fast-paced introduction that shows you some
of the Inequality Graphing application’s features.
Maximize profit, P = 3X + 2Y, for quantities of two products, X
and Y, given the following constraints on materials and time:
X |0, Y |0
Y + X 10
3X + Y {15
1. Press to display the list of
applications on your calculator.
2. Select Inequal (or Inequalz in the
international version).
The Inequality Graphing splash screen is
displayed.

Inequality Graphing for the TI-83 Plus Page 6
3. Press any key. The Y= Editor screen is
displayed.
Note that placing the cursor on = for any
Y-variable displays the new relation symbols
at the bottom of the screen.
Press plus ^–bto insert a
relation symbol.
^ _ ` a b
4. Press `to select .
5. Move the cursor to the right of the
relation symbol.
6. Press Àʹto store 10Nx to
Y1.
7. Enter the relations for Y2and Y3, as
shown.

Inequality Graphing for the TI-83 Plus Page 7
8. Move the cursor to X=(in the top left
corner).
9. Press Íto access the X=editor.
10. Press bto select .
11. Press Êto store the value to X1.
12. Press pto set up the graphing
window.
13. Change the Xmin, Xmax, Ymin, and
Ymax settings as shown.
14. Press sto graph the selected Xn
and Ynvariables.
Shades, PoI-Trace and ? (help) options
display when the graph is drawn.
Press plus ^Nbto select an
option.
^or _ ` or a b

Inequality Graphing for the TI-83 Plus Page 8
15. Press ãF1äto display the SHADES
menu.
16. Select 1:Ineq Intersection.
Inequality Graphing draws the graph
again, shading the intersection region
of the inequalities.
17. Press `to select the
PoI-Trace option. The first point of
interest is displayed.
The coordinates of the point of interest are
displayed at the bottom of the screen. The
X-variables and Y-variables that are a part of
the intersection are displayed in the top left
corner (in this case Y1and Y2).
Press }or to move from one Xnor Ynto
the next. Press ~or |to move from one
point to another along the same Xnor Yn.

Inequality Graphing for the TI-83 Plus Page 9
18. Press ;to append the coordinates
for the point at your cursor position to
the lists LINEQX (x-coordinate) and
LINEQY (y-coordinate).
19. Press any key to continue.
20. Find and store the remaining points
that bound the shaded region.
21. Press .
22. From the Edit menu, select 1:Edit.

Inequality Graphing for the TI-83 Plus Page 10
23. Insert a new list named PRFT.
24. Add the formula for maximum profit,
"3 * LINEQX + 2 * LINEQY":
Press ƒã"ä¯y9.
Scroll to LINEQX.
Press Íto select it.
Press ÃÁ¯y9.
Scroll to LINEQY.
Press Íto select it.
Press ƒã"ä.
The highest value in PRFT provides the
corresponding x (LINEQX) and y (LINEQY)
values to maximize the profit.

Inequality Graphing for the TI-83 Plus Page 11
Starting and Quitting the Inequality Graphing
Application
Note
To select a menu option, press the number or letter
corresponding to the option or press to highlight the option,
then press E.
The Inequality Graphing application works only in function mode.
If your calculator is not in function mode, the application changes
the mode.
To run the Inequality Graphing application efficiently, your
calculator should have at least 600 bytes of free RAM.
Note
Quitting the application does not delete it from your calculator. To
delete the application, see Deleting Inequality Graphing from the
TI-83 Plus.
1. Press
to display the list of
applications on your calculator.
2. Select
Inequal
(or
Inequalz in the
international version). The Inequality
Graphing information screen is
displayed.

Inequality Graphing for the TI-83 Plus Page 12
3. Press any key. The Y= Editor screen is
displayed with the cursor on the =for
Y1.
If the Inequality Graphing application is already running on your
calculator, the above screens will not be displayed when you
select Inequal (or Inequalz in the international version) from the
Applications menu. Instead, the following screen is displayed,
giving you options to quit the application or to continue (leave it
running).
Select one of the following options:
Choose
To
1:Continue
Leave the Inequality Graphing
application active
2:Quit Inequal
Deactivate the Inequality
Graphing application
3:About
View the About screen that
displays the application name
and version number

Inequality Graphing for the TI-83 Plus Page 13
A Word About AppVars
The Inequality Graphing application creates two application
variables (AppVars) when you run it. These AppVars are used to
store data specific to this application and to make graphing
faster.
•INEQVAR requires 237 bytes of free RAM. The Inequality
Graphing application requires INEQVAR to function correctly.
If your calculator does not have at least 237 bytes of free
RAM, you cannot run the Inequality Graphing application.
•POILIST requires 317 bytes of free RAM. The Inequality
Graphing application does not require POILIST to function
correctly. However, if your calculator does not have an
additional 317 bytes of free RAM so that POILIST can be
created, performance will be much slower.
INEQVAR and POILIST are automatically deleted from the
calculator’s memory when you quit Inequality Graphing normally
(from the Quit menu option). If Inequality Graphing is forced to
quit by the system, (for example, if you delete the application
manually, or if you transfer files while the application is running
and the calculator is defragmented) the AppVars remain on the
calculator, but are no longer active.

Inequality Graphing for the TI-83 Plus Page 14
Y= Editor and X= Editor
When you place the cursor over the equality symbol on the
Y= editor, you immediately see some of the features the
Inequality Graphing application offers. A set of relation options is
displayed across the bottom of the screen. You can use any
inequality symbol (>, <, |, {) as well as the equality symbol.
(These options are displayed only when the cursor is over the
relation symbol.)
The Inequality Graphing application has an X=editor to
complement the Y=editor. You access it from the Y=editor and
you can move between the two editors as much as you like. A
highlighted X= or Y= in the top left corner of the screen reminds
you that you defined and selected equations or inequalities on
the other editor.
On the X= editor, an expression must evaluate to a real number.
You can use any constant function of Xto define vertical lines,
whether they are equations or inequalities.

Inequality Graphing for the TI-83 Plus Page 15
Relation Symbols
To change a relation symbol, place the cursor on the symbol for
that Ynor Xnand use the keystrokes below to select the
appropriate symbol.
Relation Symbol
Keystrokes
^
_
`
a
b
Graph Styles
In the Y=editor, the graph style for inequalities corresponds to
the inequality and automatically changes when you select the
symbol. You cannot change this graph style. The graph style for
equations remains unchanged. You can change the graph style
to one of the seven standard TI-83 Plus options: ç, è, é, ê, ë, ì,
or í

Inequality Graphing for the TI-83 Plus Page 16
In the X=editor, all graph styles are automatically selected and
cannot be changed. Inequalities have a graph style that
corresponds to the inequality; equations have the thin line graph
style (ç).
Note
When you quit the Inequality Graphing application normally, all
inequality graph styles are changed to the thin line graph style (ç).
Inequality
Graph
Style
Relation
Symbol
Definition
Result
<
Less than
Graph is shaded below the line,
but the line is not included in the
solution, so it appears “dotted”

Less than or
equal to
Graph is shaded below the line
and the line is included in the
solution
>
Greater than
Graph is shaded above the line,
but the line is not included in the
solution, so it appears “dotted”

Greater than
or equal to
Graph is shaded above the line
and the line is included in the
solution

Inequality Graphing for the TI-83 Plus Page 17
Defining an Inequality or Equation
To define an inequality or equation in the Y=editor or X=editor,
select the relation symbol, move the cursor to the right, and
enter the inequality or equation. You do not have to change the
relation symbol before you type the inequality or equation.
Notice that when a Ynor Xnis defined, it is automatically selected
to be included in the graph. To select or deselect a Ynor Xn,
place the cursor on the relation symbol and press Í.
Example: Define the following in the Y= editor:
Y12X + 4
Y2 -5X
Y3> 0
1. Place the cursor on the =symbol for Y1.
The cursor is automatically placed over the =
symbol for Y1when you first access the Y=
editor. The relation symbol displays only
when the cursor is on a relation symbol.
Press plus ^–bto insert a
relation symbol.
^ _ ` a b

Inequality Graphing for the TI-83 Plus Page 18
2. Press `to change =to .
3. Move the cursor to the right of the
relation symbol.
4. Press ÁÃ ¶ to store 2x+4 to
Y1.
5. Move the cursor to the next Y-variable
and enter the remaining inequalities, as
shown.
Example: Define the following in the X=editor:
X1 0
1. Move the cursor to the X= symbol in the
top left corner of the screen.

Inequality Graphing for the TI-83 Plus Page 19
2. Press Íto display the X=editor
screen. The cursor is automatically
placed on the =symbol for X1.
3. Press bto change =to .
4. Move the cursor to the right of the
relation symbol.
5. Press Êto store the value to X1.

Inequality Graphing for the TI-83 Plus Page 20
Graphing
The Inequality Graphing application graphs the selected
inequalities and/or equations from the Y=editor first, then it
graphs the selected inequalities and/or equations from the
X=editor. When the graphs are displayed, three options appear
at the bottom of the screen: Shades, PoI-Trace, and ?(Help).
These options are additional features of the Inequality Graphing
application and are discussed later in this section.
Note
p, r, q, and y/work the same in Inequality
Graphing as in normal graphing.
1. Check the Y=editor and the X=editor to
be sure that the relations you want to
include on the graph are selected.
Place the cursor on the relation symbol and
press Íto select or deselect a Ynor Xn.