Texas Instruments TI-89 user guide: Using the Two-Graph Mode

Using the Two-Graph Mode

In two-graph mode, the TI-89 / TI-92 Plus's graph-related features are duplicated, giving you two independent graphing calculators. The two-graph mode is only available in split screen mode. For more information about split screens, refer to Chapter 14.

Setting the Mode

Several mode settings affect the two-graph mode, but only two settings are required. Both are on Page 2 of the MODE dialog box.

1. Press [MODE]. Then press [F2] to display Page 2.
2. Set the following required modes.
   • Split Screen = TOP-BOTTOM or LEFT-RIGHT
   • Number of Graphs = 2
3. Optionally, you can set the following modes. Page 1: * Graph = Graph mode for top or left side of the split Page 2: * Split 1 App = application for top or left side * Split 2 App = application for bottom or right side * Graph 2 = Graph mode for bottom or right side * Split Screen Ratio = relative sizes of the two sides (TI-92 Plus only)
4. Press [ENTER] to close the dialog box.

The Two-Graph Screen

A two-graph screen is similar to a regular split screen.

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Independent Graph-Related Features

Both Graph 1 and Graph 2 have independent:

• Graph modes (FUNCTION, POLAR, etc.). Other modes such as Angle, Display Digits, etc., are shared and affect both graphs.
• Window Editor variables.
• Table setup parameters and Table screens.
• Graph formats such as Coordinates, Axes, etc.
• Graph screens.
• Y= Editors. However, both graphs share common function and stat plot definitions.

Note: The Y= Editor is completely independent only when the two sides use different graphing modes (as described below).

Independent graph-related applications (Y= Editor, Graph screen, etc.) can be displayed on both sides of the screen at the same time.

Non-graph-related applications (Home screen, Data/Matrix Editor, etc.) are shared and can be displayed on only one side at a time.

The Y= Editor in Two-Graph Mode

Even in two-graph mode, there is actually only one Y= Editor, which maintains a single function list for each Graph mode setting. However, if both sides use the same graphing mode, each side can select different functions from that single list.

• When both sides use different graphing modes, each side shows a different function list.

• When both sides use the same graphing mode, each side shows the same function list.

  • You can use F4 to select different functions and stat plots (indicated by ✓) for each side.
  • If you set a display style for a function, that style is used by both sides. (TI-89: 2nd F6] TI-92 Plus: [F6])

Note: If you make a change on the active Y= Editor (redefine a function, change a style, etc.), that change is not reflected on the inactive side until you switch to it.

Suppose Graph 1 and Graph 2 are set for function graphing. Although both sides show the same function list, you can select (✓) different functions for graphing.

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Using a Split Screen

Note: You can display non-graph-related applications (such as the Home screen) on only one side at a time.

For more complete information about split screens, refer to Chapter 14.

• To switch from one graph side to the other, press \underline2nd [APPS] (second function of [APPS]).
• To display different applications:
  • Switch to the applicable graph side and display the application as you normally would. — or —
  • Use \underlineMODE to change Split 1 App and/or Split 2 App.
• To exit two-graph mode:
  • Use \underlineMODE to set Number of Graphs = 1, or exit the split screen by setting Split Screen = FULL. — or —
  • Press \underline2nd [QUIT] twice. This always exits a split screen and returns to a full-sized Home screen.

Remember that the Two Sides Are Independent

In two-graph mode, the two sides may appear to be related when, in fact, they are not. For example:

For Graph 1, the Y= Editor lists y(x) functions.

For Graph 2, the polar graph uses r(θ) equations that are not shown.

From the Home Screen or a Program

After the two-graph mode is set up, graph-related operations refer to the active graph side. For example:

10→xmax

affects either Graph 1 or Graph 2, depending on which is active when you execute the command.

To switch the active sides, press \underline2nd [APPS] or use the switch function, switch(1) or switch(2).

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Drawing a Function or Inverse on a Graph

For comparison purposes, you may want to draw a function over your current graph. Typically, the drawn function is some variation of the graph. You can also draw the inverse of a function. (These operations are not available for 3D graphs.)

Drawing a Function, Parametric, or Polar Equation

Execute DrawFunc, DrawParm, or DrawPol from the Home screen or a program. You cannot draw a function or equation interactively from the Graph screen.

DrawFunc expression DrawParm expression1, expression2 [tmin] [tmax] [tstep] DrawPol expression [θmin] [θmax] [θstep]

For example:

1. Define y1(x)=.1x³−2x+6 on the Y= Editor, and graph the function.

To display the Home screen and put DrawFunc in the entry line, press: TI-89: [2nd] [F6] 2 TI-92 Plus: [F6] 2

2. On the Graph screen, press: TI-89: [2nd] [F6] TI-92 Plus: [F6] and select 2:DrawFunc.

3. On the Home screen, specify the function to draw.

DrawFunc y1(x)−6

Tip: To clear the drawn function, press [F4] — or — TI-89: [2nd] [F6] and select 1:ClrDraw. TI-92 Plus: [F6] and select 1:ClrDraw.

4. Press [ENTER] to draw the function on the Graph screen.

You cannot trace, zoom, or perform a math operation on a drawn function.

Drawing the Inverse of a Function

Execute DrawInv from the Home screen or a program. You cannot draw an inverse function interactively from the Graph screen.

DrawInv expression

For example, use the graph of y1(x)=.1x³−2x+6 as shown above.

To display the Home screen and put DrawInv in the entry line, press: TI-89: [2nd] [F6] 3 TI-92 Plus: [F6] 3

1. On the Graph screen, press: TI-89: [2nd] [F6] TI-92 Plus: [F6] and select 3:DrawInv.

2. On the Home screen, specify the inverse function.

DrawInv y1(x)

3. Press [ENTER].

The inverse is plotted as (y,x) instead of (x,y).

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Drawing a Line, Circle, or Text Label on a Graph

You can draw one or more objects on the Graph screen, usually for comparisons. For example, draw a horizontal line to show that two parts of a graph have the same y value. (Some objects are not available for 3D graphs.)

Clearing All Drawings

Tip: You can also enter ClrDraw on the Home screen’s entry line.

A drawn object is not part of the graph itself. It is drawn “on top of” the graph and remains on the screen until you clear it.

From the Graph screen:

• TI-89: [2nd] [F6]
  TI-92 Plus: [F6]
  and select 1:ClrDraw.
  — or —
• Press [F4] to regraph.

You can also do anything that causes the Smart Graph feature to redraw the graph (such as change the Window variables or deselect a function on the Y= Editor).

Drawing a Point or a Freehand Line

Tip: When drawing a freehand line, you can move the cursor diagonally.

From the Graph screen:

1. TI-89: [2nd] [F7]
   TI-92 Plus: [F7]
   and select 1:Pencil.
2. Move the cursor to the applicable location.

Note: If you start drawing on a white pixel, the pencil draws a black point or line. If you start on a black pixel, the pencil draws a white point or line (which can act as an eraser).

After drawing the point or line, you are still in “pencil” mode.

• To continue drawing, move the cursor to another point.
• To quit, press [ESC].

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Erasing Individual Parts of a Drawing Object

From the Graph screen:

1. TI-89: [2nd] [F7] TI-92 Plus: [F7] and select 2:Eraser. The cursor is shown as a small box.

2. Move the cursor to the applicable location.

After erasing, you are still in “eraser” mode.

• To continue erasing, move the box cursor to another location.
• To quit, press [ESC].

Note: These techniques also erase parts of graphed functions.

Drawing a Line Between Two Points

From the Graph screen:

1. TI-89: [2nd] [F7] TI-92 Plus: [F7] and select 3:Line.

2. Move the cursor to the 1st point, and press [ENTER].

3. Move to the 2nd point, and press [ENTER]. (As you move, a line extends from the 1st point to the cursor.)

After drawing the line, you are still in “line” mode.

• To continue drawing another line, move the cursor to a new 1st point.
• To quit, press [ESC].

Tip: Use [2nd] to move the cursor in larger increments; [2nd] [→], etc.

Drawing a Circle

From the Graph screen:

1. TI-89: [2nd] [F7] TI-92 Plus: [F7] and select 4:Circle.

2. Move the cursor to the center of the circle, and press [ENTER].

3. Move the cursor to set the radius, and press [ENTER].

Tip: Use [2nd] to move the cursor in larger increments; [2nd] [→], etc.

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Drawing a Horizontal or Vertical Line

Tip: Use \boxed2nd to move the cursor in larger increments; \boxed2nd \boxed\circ, etc.

From the Graph screen:

1. TI-89: \boxed2nd \boxedF7 TI-92 Plus: \boxedF7 and select 5:Horizontal or 6:Vertical. A horizontal or vertical line and a flashing cursor are displayed on the screen. If the line is initially displayed on an axis, it may be difficult to see. However, you can easily see the flashing cursor.
2. Use the cursor pad to move the line to the appropriate position. Then press \boxedENTER.

After drawing the line, you are still in "line" mode.

• To continue, move the cursor to another location.
• To quit, press \boxedESC.

Drawing a Tangent Line

Tip: To set the tangent point, you can also type its x value and press \boxedENTER.

To draw a tangent line, use the \boxedF5 Math toolbar menu. From the Graph screen:

1. Press \boxedF5 and select A:Tangent.
2. As necessary, use \boxed\ominus and \boxed\oplus to select the applicable function.
3. Move the cursor to the tangent point, and press \boxedENTER.

The tangent line is drawn, and its equation is displayed.

Drawing a Line Based on a Point and a Slope

To draw a line through a specified point with a specified slope, execute the DrawSlp command from the Home screen or a program. Use the syntax:

DrawSlp x, y, slope

You can also access DrawSlp from the Graph screen.

1. TI-89: \boxed2nd \boxedF6 TI-92 Plus: \boxedF6 and select 6:DrawSlp. This switches to the Home screen and puts DrawSlp in the entry line.
2. Complete the command, and press \boxedENTER.

\boxedDrawSlp 4,0,6.37

The TI-89 / TI-92 Plus automatically switches to the Graph screen and draws the line.

Chapter 12: Additional Graphing Topics 215

Typing Text Labels

Tip: The text cursor indicates the upper-left corner of the next character you type.

From the Graph screen:

1. TI-89: [2nd] [F7] TI-92 Plus: [F7] and select 7:Text.
2. Move the text cursor to the location where you want to begin typing.
3. Type the text label.

After typing the text, you are still in "text" mode.

• To continue, move the cursor to another location.
• To quit, press [ENTER] or [ESC].

From the Home Screen or a Program

Commands are available for drawing any of the objects described in this section. There are also commands (such as PxlOn, PxlLine, etc.) that let you draw objects by specifying exact pixel locations on the screen.

For a list of the available drawing commands, refer to "Drawing on the Graph Screen" in Chapter 17.

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Saving and Opening a Picture of a Graph

You can save an image of the current Graph screen in a PICTURE (or PIC) variable. Then, at a later time, you can open that variable and display the image. This saves the image only, not the graph settings used to produce it.

Saving a Picture of the Whole Graph Screen

A picture includes any plotted functions, axes, tick marks, and drawn objects. The picture does not include lower and upper bound indicators, prompts, or cursor coordinates.

Display the Graph screen as you want to save it. Then:

1. Press F1 and select 2:Save Copy As.
2. Specify the type (Picture), folder, and a unique variable name.
3. Press ENTER. After typing in an input box such as Variable, you must press ENTER twice.

Important: By default, Type = GDB (for graph database). You must set Type = Picture.

Saving a Portion of the Graph Screen

You can define a rectangular box that encloses only the portion of the Graph screen that you want to save.

Note: You cannot save a portion of a 3D graph.

Tip: Use \leftarrow and \rightarrow to move the top or bottom, and use \uparrow and \downarrow to move the sides.

1. TI-89: [2nd] [F7] TI-92 Plus: [F7] and select 8:Save Picture.

A box is shown around the outer edge of the screen.

2. Set the 1st corner of the box by moving its top and left sides. Then press ENTER.
3. Set the 2nd corner by moving the bottom and right sides. Then press ENTER.
4. Specify the folder and a unique variable name.
5. Press ENTER. After typing in an input box such as Variable, you must press ENTER twice.

Note: When saving a portion of a graph, Type is automatically fixed as Picture.

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Opening a Graph Picture

When you open a graph picture, it is superimposed over the current Graph screen. To display only the picture, use the Y= Editor to deselect any other functions before opening the graph picture.

From the Graph screen:

1. Press F1 and select 1:Open.
2. Select the type (Picture), folder, and variable that contain the graph picture you want to open.

Note: If a variable name is not shown on the dialog box, there are no graph pictures in the folder.

3. Press ENTER.

Important: By default, Type = GDB (for graph database). Be sure to set Type = Picture.

A graph picture is a drawing object. You cannot trace any curve on a picture.

For Pictures Saved from a Portion of the Graph Screen

When you press F1 and select 1:Open, the picture is superimposed starting at the upper-left corner of the Graph screen. If the picture was saved from a portion of the Graph screen (page 217), it may appear shifted from the underlying graph.

To specify which screen pixel to use as the upper-left corner, you can use the commands listed in "From a Program or the Home Screen" below.

Deleting a Graph Picture

Unwanted Picture variables take up calculator memory. To delete a variable, use the VAR-LINK screen (2nd [VAR-LINK]) as described in Chapter 21.

From a Program or the Home Screen

To save (store) and open (recall) a graph picture, use the StoPic, RclPic, AndPic, XorPic, and RplcPic commands as described in Appendix A.

To display a series of graph pictures as an animation, use the CyclePic command. For an example, refer to page 219.

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Animating a Series of Graph Pictures

As described earlier in this chapter, you can save a picture of a graph. By using the CyclePic command, you can flip through a series of graph pictures to create an animation.

CyclePic Command

Before using CyclePic, you must have a series of graph pictures that have the same base name and are sequentially numbered starting with 1 (such as pic1, pic2, pic3, . . . ).

To cycle the pictures, use the syntax:

CyclePic picNameString, n [wait] [cycles] [direction]

Example

This example program (named cyc) generates 10 views of a 3D graph, with each view rotated 10° further around the Z axis. For information about each command, refer to Appendix A. For information about using the Program Editor, refer to Chapter 17.

Comments start with . Press: TI-89: [F4] [1] TI-92 Plus: [2nd] X

For \phi, press: TI-89: [F4] [alpha] F TI-92 Plus: [F4] G F

For #, press TI-89: [CATALOG] TI-92 Plus: [2nd][CATALOG] and select it from the list.

For &, press: TI-89: [F4] [x] TI-92 Plus: [2nd] H

Note: Due to its complexity, this program takes several minutes to run.

Program Listing Every Other Graph from Program

\begin{tabular}{ll} :cyc() & \ :Prgm & \ :local i & \ :ⒸSet mode and Window variables & \ :setMode("graph","3d") & \ :70\rightarroweye\phi & \ :-10\rightarrowxmin & \ :10\rightarrowxmax & \ :14\rightarrowxgrid & \ :-10\rightarrowymin & \ :10\rightarrowymax & \ :14\rightarrowygrid & \ :-10\rightarrowzmin & \ :10\rightarrowzmax & \ :1\rightarrowzscl & \ :ⒸDefine the function & \ :(x^{}3y-y^{}3x)/390\rightarrowzl(x,y) & \ :ⒸGenerate pics and rotate & \ :For i,1,10,1 & \ :i*10\rightarroweye\theta & \ : DispG & \ : StoPic #("pic" & string(i)) & \ :EndFor & \ :ⒸDisplay animation & \ :CyclePic "pic",10,.5,5,-1 & \ :EndPrgm & \ \end{tabular}

After entering this program on the Program Editor, go to the Home screen and enter cyc().

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Saving and Opening a Graph Database

A graph database is the set of all elements that define a particular graph. By saving a graph database as a GDB variable, you can recreate that graph at a later time by opening its stored database variable.

Elements in a Graph Database

A graph database consists of:

• Mode settings (MODE) for Graph, Angle, Complex Format, and Split Screen (only if you are using the two-graph mode).
• All functions in the Y= Editor (Y=), including display styles and which functions are selected.
• Table parameters (TblSet), Window variables (WINDOW), and graph formats (F1 9 — or — TI-89: 1 TI-92 Plus: F.)

Note: In two-graph mode, the elements for both graphs are saved in a single database.

A graph database does not include drawn objects or stat plots.

Saving the Current Graph Database

From the Y= Editor, Window Editor, Table screen, or Graph screen:

1. Press F1 and select 2:Save Copy As.
2. Specify the folder and a unique variable name.
3. Press ENTER. After typing in an input box such as Variable, you must press ENTER twice.

Note: If you start from the Graph screen, be sure to use Type=GDB.

Opening a Graph Database

Caution: When you open a graph database, all information in the current database is replaced. You may want to store the current graph database before opening a stored database.

From the Y= Editor, Window Editor, Table screen, or Graph screen:

1. Press F1 and select 1:Open.
2. Select the folder and variable that contain the graph database you want to open.
3. Press ENTER.

Note: If you start from the Graph screen, be sure to use Type=GDB.

Deleting a Graph Database

Unused GDB variables take up calculator memory. To delete them, use the VAR-LINK screen (2nd [VAR-LINK]) described in Chapter 21.

From a Program or the Home Screen

You can save (store) and open (recall) a graph database by using the StoGDB and RclGDB commands as described in Appendix A.

220 Chapter 12: Additional Graphing Topics

Tables

13

• Preview of Tables ........ 222
• Overview of Steps in Generating a Table ........ 223
• Setting Up the Table Parameters ........ 224
• Displaying an Automatic Table ........ 226
• Building a Manual (Ask) Table ........ 229

Previously, in Chapter 6: Basic Function Graphing, you learned how to define and graph a function.

By using a table, you can display a defined function in a tabular form.

Y= Editor shows an algebraic representation.

Note: Tables are not available in 3D Graph mode.

Table screen shows a numeric representation.

Graph screen shows a graphic representation.

The table lists a series of values for the independent variable and shows the corresponding value of the dependent variable.

Independent variable

$$y(x) = x^3 - 2x$$

Dependent variable

Chapter 13: Tables 221

Preview of Tables

Evaluate the function y=x³–2x at each integer between -10 and 10. How many sign changes are there, and where do they occur?

222 Chapter 13: Tables

Overview of Steps in Generating a Table

To generate a table of values for one or more functions, use the general steps shown below. For specific information about setting table parameters and displaying the table, refer to the following pages.

Generating a Table

Note: Tables are not available in 3D Graph mode.

Tip: For information on defining and selecting functions with the Y= Editor, refer to Chapter 6.

Tip: You can specify: • An automatic table – Based on initial values. – That matches a graph. • A manual (ask) table.

Exploring the Table

From the Table screen, you can: • Scroll through the table to see values on other pages. • Highlight a cell to see its full value. • Change the table’s setup parameters. By changing the starting or incremental value used for the independent variable, you can zoom in or out on the table to see different levels of detail. • Change the cell width. • Edit selected functions. • Build or edit a manual table to show only specified values of the independent variable.

Chapter 13: Tables 223

Setting Up the Table Parameters

To set up the initial parameters for a table, use the TABLE SETUP dialog box. After the table is displayed, you can also use this dialog box to change the parameters.

Displaying the TABLE SETUP Dialog Box

To display the TABLE SETUP dialog box, press ◆[TblSet]. From the Table screen, you can also press [F2].

Note: The table initially starts at tblStart, but you can use ◀ to scroll to prior values.

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Which Setup Parameters to Use

\begin{tabular}{lllll} To generate: & tblStart & \Deltatbl & Graph $<-$Table & Independent \ An automatic table & & & & \ \bullet Based on initial values & value & value & OFF & AUTO \ \bullet That matches Graph screen & --- & --- & ON & AUTO \ A manual table & --- & --- & --- & ASK \ \end{tabular}

“---” means that any value entered for this parameter is ignored for the indicated type of table.

In SEQUENCE graphing mode (Chapter 9), use integers for tblStart and \Deltatbl.

Changing the Setup Parameters

From the TABLE SETUP dialog box:

1. Use \ominus and \oplus to highlight the value or setting to change.
2. Specify the new value or setting.

\begin{tabular}{ll} To change: & Do this: \ tblStart or \Deltatbl & Type the new value. The existing value is erased when you start to type. \ & — or — \ & Press \textcircled\small\uparrow or \textcircled\small\downarrow to remove the highlighting. Then edit the existing value. \ Graph $<-$ Table or Independent & Press \textcircled\small\leftarrow or \textcircled\small\rightarrow to display a menu of valid settings. Then either: \ & \bullet Move the cursor to highlight the setting and press \texttt{ENTER}. \ & — or — \ & \bullet Press the number for that setting. \ \end{tabular}

Tip: To cancel a menu or exit the dialog box without saving any changes, press \texttt{ESC} instead of \texttt{ENTER}.

3. After changing all applicable values or settings, press \texttt{ENTER} to save your changes and close the dialog box.

From the Home Screen or a Program

You can set up a table’s parameters from the Home screen or a program. You can:

• Store values directly to the system variables tblStart and \Deltatbl. Refer to “Storing and Recalling Variable Values” in Chapter 2.
• Set Graph $<-$ Table and Independent by using the setTable function. Refer to Appendix A.

Chapter 13: Tables 225

Displaying an Automatic Table

If Independent = AUTO on the TABLE SETUP dialog box, a table is generated automatically when you display the Table screen. If Graph <-> Table = ON, the table matches the trace values from the Graph screen. If Graph <-> Table = OFF, the table is based on the values you entered for tblStart and \Deltatbl.

Before You Begin

Define and select the applicable functions on the Y= Editor (2nd [Y=]). This example uses $y1(x) = x^3 - x/3$.

Then enter the initial table parameters (2nd [TblSet]).

Displaying the Table Screen

To display the Table screen, press [TABLE] or [APPS] 5.

The cursor initially highlights the cell that contains the starting value of the independent variable. You can move the cursor to any cell that contains a value.

First column shows values of the independent variable.

Other columns show corresponding values of the functions selected in the Y= Editor.

Tip: You can scroll back from the starting value by pressing \ominus or [2nd] \oplus.

Header row shows names of independent variable (x) and selected functions (y1).

Entry line shows full value of highlighted cell.

To move the cursor: Press: One cell at a time \ominus, \oplus, \odot, or \oslash One page at a time [2nd] and then \ominus, \oplus, \odot, or \oslash

The header row and the first column are fixed so that they cannot scroll off the screen.

• When you scroll down or up, the variable and function names are always visible across the top of the screen.
• When you scroll right or left, the values of the independent variable are always visible along the left side of the screen.

226 Chapter 13: Tables

Changing the Cell Width

Cell width determines the maximum number of digits and symbols (decimal point, minus sign, and “E” for scientific notation) that can be displayed in a cell. All cells in the table have the same width.

To change the cell width from the Table screen:

1. Press F1 9
   — or —
   TI-89: ♦ 1
   TI-92 Plus: ♦ F.

2. Press ↑ or ↓ to display a menu of valid widths (3 – 12).

3. Move the cursor to highlight a number and press ENTER. (For single-digit numbers, you can type the number and press ENTER.)

4. Press ENTER to close the dialog box and update the table.

Note: By default, the cell width is 6.

How Numbers Are Displayed in a Cell

Whenever possible, a number is shown according to the currently selected display modes (Display Digits, Exponential Format, etc.). The number may be rounded as necessary. However:

• If a number’s magnitude is too large for the current cell width, the number is rounded and shown in scientific notation.
• If the cell width is too narrow even for scientific notation, “...” is shown.

By default, Display Digits = FLOAT 6. With this mode setting, a number is shown with up to six digits, even if the cell is wide enough to show more. Other settings similarly affect a displayed number.

Note: If a function is undefined at a particular value, undef is displayed in the cell.

Tip: Use MODE to set the display modes.

Tip: To see a number in full precision, highlight the cell and look at the entry line.

Note: Depending on display mode settings, some values are not shown in full precision even when the cell is wide enough.

If Results are Complex Numbers

A cell shows as much as possible of a complex number (according to the current display modes) and then shows “...” at the end of the displayed portion.

When you highlight a cell containing a complex number, the entry line shows the real and imaginary parts with a maximum of four digits each (FLOAT 4).

Chapter 13: Tables 227

Editing a Selected Function

From a table, you can change a selected function without having to use the Y= Editor.

1. Move the cursor to any cell in the column for that function. The table’s header row shows the function names (y1, etc.).
2. Press F4 to move the cursor to the entry line, where the function is displayed and highlighted.
3. Make any changes, as necessary.
   • Type the new function. The old function is erased when you begin typing. — or —
   • Press CLEAR to clear the old function. Then type the new one. — or —
   • Press ◀ or ▶ to remove the highlighting. Then edit the function.
4. Press ENTER to save the edited function and update the table. The edited function is also saved in the Y= Editor.

Tip: You can use this feature to view a function without leaving the table.

Tip: To cancel any changes and return the cursor to the table, press ESC instead of ENTER.

If You Want to Change the Setup Parameters

After generating an automatic table, you can change its setup parameters as necessary.

Press F2 or 4 [TblSet] to display the TABLE SETUP dialog box. Then make your changes as described on pages 224 and 225.

228 Chapter 13: Tables

Building a Manual (Ask) Table

If Independent = ASK on the TABLE SETUP dialog box, the TI-89 / TI-92 Plus lets you build a table manually by entering specific values for the independent variable.

Displaying the Table Screen

To display the Table screen, press \blacklozenge [TABLE] or [APPS] 5.

If you set Independent = ASK (with \blacklozenge [TblSet]) before displaying a table for the first time, a blank table is displayed. The cursor highlights the first cell in the independent variable column.

Header row shows names of independent variable (x) and selected functions (y1).

Enter a value here.

If you first display an automatic table and then change it to Independent = ASK, the table continues to show the same values. However, you can no longer see additional values by scrolling up or down off the screen.

Entering or Editing an Independent Variable Value

You can enter a value in column 1 (independent variable) only.

1. Move the cursor to highlight the cell you want to enter or edit.
   • If you start with a blank table, you can enter a value in consecutive cells only (row 1, row 2, etc.). You cannot skip cells (row 1, row 3).
   • If a cell in column 1 contains a value, you can edit that value.

Tip: To enter a new value in a cell, you do not need to press F3. Simply begin typing.

2. Press F3 to move the cursor to the entry line.
3. Type a new value or expression, or edit the existing value.
4. Press [ENTER] to move the value to the table and update the corresponding function values.

The cursor returns to the entered cell. You can use \rightarrow to move to the next row.

Note: In this example, you can move the cursor to column 2, but you can enter values in column 1 only.

Enter values in any numerical order.

Enter a new value here.

Shows full value of highlighted cell.

Chapter 13: Tables 229

Entering a List in the Independent Variable Column

1. Move the cursor to highlight any cell in the independent variable column.
2. Press [F4] to move the cursor to the entry line.
3. Type a series of values, enclosed in braces { } and separated by commas. For example:

x={1,1.5,1.75,2}

You can also enter a list variable or an expression that evaluates to a list.

4. Press [ENTER] to move the values into the independent variable column. The table is updated to show the corresponding function values.

Note: If the independent variable column contains existing values, they are shown as a list (which you can edit).

Adding, Deleting, or Clearing

Cell Width and Display Formats

Several factors affect how numbers are displayed in a table. Refer to “Changing the Cell Width” and “How Numbers Are Displayed in a Cell” on page 227.

From the Home Screen or a Program

System variable tblInput contains a list of all independent variable values entered in the table, even those not currently displayed. tblInput is also used for an automatic table, but it contains only the independent variable values that are currently displayed.

Before displaying a table, you can store a list of values directly to the tblInput system variable.

230 Chapter 13: Tables

Split Screens

14

• Preview of Split Screens ........ 232
• Setting and Exiting the Split Screen Mode ........ 233
• Selecting the Active Application ........ 235

On the TI-89 / TI-92 Plus, you can split the screen to show two applications at the same time.

For example, it may be helpful to show both the Y= Editor and the Graph screen so that you can see the list of functions and how they are graphed.

Chapter 14: Split Screens 231

Preview of Split Screens

Split the screen to show the Y= Editor and the Graph screen. Then explore the behavior of a polynomial as its coefficients change.

232 Chapter 14: Split Screens

Setting and Exiting the Split Screen Mode

To set up a split screen, use the MODE dialog box to specify the applicable mode settings. After you set up the split screen, it remains in effect until you change it.

Setting the Split Screen Mode

1. Press MODE to display the MODE dialog box.
2. Because the modes related to split screens are listed on the second page of the MODE dialog box, either:
   • Use ▼ to scroll down.
   • — or —
   • Press F2 to display Page 2.
3. Set the Split Screen mode to either of the following settings. For the procedure used to change a mode setting, refer to Chapter 2.

Split Screen Settings TOP-BOTTOM LEFT-RIGHT

When you set Split Screen = TOP-BOTTOM or LEFT-RIGHT, previously dimmed modes such as Split 2 App become active.

Setting the Initial Applications

Before pressing ENTER to close the MODE dialog box, you can use the Split 1 App and Split 2 App modes to select the applications you want to use.

Note: In two-graph mode, described in Chapter 12, the same application can be in both parts of a split screen.

If you set Split 1 App and Split 2 App to the same application, the TI-89 / TI-92 Plus exits the split screen mode and displays the application full screen.

You can open different applications after the split screen is displayed, as described on page 235.

Chapter 14: Split Screens 233