Texas Instruments TI-89 user guide: Typing Accent Marks from the TI-92 Plus Keyboard

Typing Accent Marks from the TI-92 Plus Keyboard

Pressing an accent mark key does not display an accented letter. The accent mark will be added to the next letter you press.

1. Press [2nd] and then the key for the accent mark.
2. Press the key for the letter you want to accent.

• You can accent lowercase and uppercase letters.
• An accent mark can be added to only those letters that are valid for that mark.

Note: To help you find the applicable keys, this map shows only the accent mark keys.

Typing Greek Letters from the Keyboard

Press the key combination that accesses the Greek character set on your calculator. Then select the applicable alpha character on the keyboard to enter a Greek letter.

On the TI-89:

Press [♦] [α] to access the Greek character set.

On the TI-92 Plus:

Press [2nd] G to access the Greek character set.

Note: Neither calculator displays a map of Greek letters. The maps shown here are for reference only.

If you press a key combination that does not access a Greek letter, you get the normal letter for that key.

326 Chapter 18: Text Editor

Several keys let you access lowercase and uppercase Greek letters.
For example:

The exact keys that you press on the TI-89 depend on whether alpha-lock is on or off. For example:

Important: If you press [alpha] on the TI-89 to access a Greek letter while alpha-lock is on, it turns alpha-lock off.

For a List of All Special Characters

For a list of all special characters, refer to Appendix B.

Chapter 18: Text Editor 327

Entering and Executing a Command Script

By using a command script, you can use the Text Editor to type a series of command lines that can be executed at any time on the Home screen. This lets you create interactive example scripts in which you predefine a series of commands and then execute them individually.

I nserting a Command Mark

Note: This does not insert a new line for the command, it simply marks an existing line as a command line.

In the Text Editor:

1. Place the cursor on the line for the command.
2. Press F2 to display the Command toolbar menu.
3. Select 1:Command.

"C" is displayed at the beginning of the text line (to the left of the colon).

Tip: You can mark a line as a command either before or after typing the command on that line.

4. Type a command just as you would on the Home screen.

The line can contain only the command, with no additional text.

You can type multiple commands on the same line if you type a colon to separate the commands.

Deleting a Command Mark

This deletes only the "C" mark; it does not delete the command text itself.

1. Place the cursor anywhere on the marked line.
2. Press F2 and select 4:Clear command.

Executing a Command

To execute a command, you must first mark the line with a "C". If you execute a line that is not marked with "C", it will be ignored.

1. Place the cursor anywhere on the command line.
2. Press F4.

Tip: To examine the result on the Home screen, use a split screen or press: TI-89: [HOME] TI-92 Plus: [HOME]

The command is copied to the entry line on the Home screen and executed. The Home screen is displayed temporarily during execution, and then the Text Editor is redisplayed.

After execution, the cursor moves to the next line in the script so that you can continue to execute a series of commands.

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Splitting the Text Editor/ Home Screen

With a split screen, you can view your command script and see the result of an executed command at the same time.

You can also use [MODE] to set up a split screen manually. However, [F3] sets up a Text Editor/Home screen split much easier than [MODE].

• The active application is indicated by a thick border. (By default, the Text Editor is the active application.)
• To switch between the Text Editor and the Home screen, press [2nd] [□□] (second function of [APPS]).

Creating a Script from Your Home Screen Entries

From the Home screen, you can save all the entries in the history area to a text variable. The entries are automatically saved in a script format so that you can open the text variable in the Text Editor and execute the entries as commands.

For information, refer to “Saving the Home Screen Entries as a Text Editor Script” in Chapter 5.

Example

1. Type your script. Press [F2] and select 1:Command to mark the command lines.
2. Press [F3] and select 1:Script view.
3. Move the cursor to the first command line. Then press [F4] to execute the command.
4. Continue using [F4] to execute each command, but stop just before executing the Graph command.
5. Execute the Graph command.
6. Press [F3] and select 2:Clear split to return to a full screen Text Editor.

Note: Some commands take longer to execute. Wait until the Busy indicator disappears before pressing [F4] again.

Note: In this example, the Graph command displays the Graph screen in place of the Home screen.

Chapter 18: Text Editor 329

Creating a Lab Report

If you have a TI-GRAPH LINK™ cable, an optional accessory that lets the TI-89 / TI-92 Plus communicate with a personal computer, you can create lab reports. Use the Text Editor to write a report, which can include print objects. Then use the TI-GRAPH LINK software to print the report on the printer attached to the computer.

Print Objects

In the Text Editor, you can specify a variable name as a print object. When you print the report by using TI-GRAPH LINK, the TI-89 / TI-92 Plus substitutes the contents of the variable (an expression, picture, list, etc.) in place of the variable name.

Inserting a Print Object Mark

In the Text Editor:

1. Place the cursor on the line for the print object.
2. Press F2 to display the Command toolbar menu.
3. Select 3:PrintObj.

“P” is displayed at the beginning of the text line (to the left of the colon).

Note: This does not insert a new line for the print object, it simply marks an existing line as a print object.

Tip: You can mark a line as a print object either before or after typing a variable name on that line.

4. Type the name of the variable that contains the print object.

The line can contain only the variable name, with no additional text.

Inserting a Page Break Mark

When you print a lab report, page breaks occur automatically at the bottom of each printed page. However, you can manually force a page break at any line.

1. Place the cursor on the line that you want to print on the top of the next page. (The line can be blank or you can enter text on it.)
2. Press F2 and select 2:Page break.

A “¶” is displayed at the beginning of the line (to the left of the colon).

Deleting a Print Object or Page Break Mark

This deletes only the “P” or “¶” mark; it does not delete any text that is on the line.

1. Place the cursor anywhere on the marked line.
2. Press F2 and select 4:Clear command.

330 Chapter 18: Text Editor

Printing the Report

Example

Assume you have stored:

• A function as y1(x) (specify y1, not y1(x)).
• A graph picture as pic1.
• Applicable information in variables der and sol.

When you print the lab report, the contents of the print objects are printed in place of their variable names.

Note: To store the derivative to variable der, enter: d(y1(x),x)→der

Note: To store the derivative’s critical points to variable sol, enter: solve(der=0,x)→sol

In cases where a graph picture cannot fit on the current page, the entire picture is shifted to the top of the next page.

Chapter 18: Text Editor 331

332 Chapter 18: Text Editor

Numeric Solver

19

• Preview of the Numeric Solver ........ 334
• Displaying the Solver and Entering an Equation ........ 335
• Defining the Known Variables ........ 337
• Solving for the Unknown Variable ........ 339
• Graphing the Solution ........ 340

The Numeric Solver lets you enter an expression or equation, define values for all but one unknown variable, and then solve for the unknown variable.

Note: To solve for the unknown variable from the Home screen or a program, use nSolve() as described in Appendix A.

After entering an equation and its known values, place the cursor on the unknown variable and press F2.

You can also graph the solution.

The x axis is the unknown variable. The y axis is the left-rt value, which gives the solution's accuracy.

The solution is precise where the curve crosses the x axis.

As in the example above, the Numeric Solver is often used to solve closed-form equations. But it also gives you a quick way to solve equations such as transcendental equations in which there is no closed form.

For example, you could rearrange the following equation manually to solve for any of the variables.

a = (m2 - m1) / (m2 + m1) * g \longrightarrow m1 = (g - a) / (g + a) * m2

With an equation such as the following, however, it may not be as easy to solve for x manually.

$y = x + e^x$

The Numeric Solver is particularly useful for such equations.

Chapter 19: Numeric Solver 333

Preview of the Numeric Solver

Consider the equation a=(m2−m1)/(m2+m1)*g, where the known values are m2=10 and g=9.8. If you assume that a=1/3 g, find the value of m1.

334 Chapter 19: Numeric Solver

Displaying the Solver and Entering an Equation

After you display the Numeric Solver, start by entering the equation that you want to solve.

Displaying the Numeric Solver

To display the Numeric Solver, press [APPS] 9.

The Numeric Solver screen shows the last entered equation, if any.

Entering an Equation

On the eqn: line, type in your equation.

Tips: In your equation:

• Do not use system function names (such as y1(x) or r1(θ)) as simple variables (y1 or r1).
• Be careful with implied multiplication. For example, a(m2+m1) is treated as a function reference, not as a*(m2+m1).

Note: When you define the variables, you can either define exp or solve for it.

Note: After you press [ENTER] the current equation is stored automatically to the system variable eqn.

Chapter 19: Numeric Solver 335

Recalling Previously Entered Equations

Your most recently entered equations (up to 11 with the default setting) are retained in memory. To recall one of these equations:

1. From the Numeric Solver screen, press F5.

A dialog box displays the most recently entered equation.

Tip: You can specify how many equations are retained. From the Numeric Solver, press F1 and select 9:Format (or use TI-89: \blacktriangleright 1] TI-92 Plus: \blacktriangleright F). Then select a number from 1 through 11.

2. Select an equation.
   • To select the displayed equation, press ENTER.
   • To select a different equation, press \blackcirclearrowright to display a list. Then select the one you want.

Only unique equations are listed. If you re-enter the same equation 5 times, it appears only once.

3. Press ENTER.

Saving Equations for Future Use

Because the number of equations that you can recall with F5 Eqns is limited, a particular equation may not be retained indefinitely.

To store the current equation for future use, save it to a variable.

1. From the Numeric Solver screen, press F1 and select 2:Save Copy As.

Note: An equation variable has an EXPR data type, as shown on the MEMORY and VAR-LINK screens.

2. Specify a folder and a variable name for the equation.

3. Press ENTER twice.

Opening a Saved Equation

To open a previously saved equation variable:

1. From the Numeric Solver screen, press F1 and select 1:Open.

2. Select the applicable folder and equation variable.

3. Press ENTER.

Variable eqn contains the current equation; it always appears alphabetically in the list.

336 Chapter 19: Numeric Solver

Defining the Known Variables

After you type an equation in the Numeric Solver, enter the applicable values for all variables except the unknown variable.

Defining the List of Variables

Note: If an existing variable is locked or archived, you cannot edit its value.

After typing your equation on the eqn: line, press ENTER or \mathbbO.

The screen lists the variables in the order they appear in the equation. If a variable is already defined, its value is shown. You can edit these variable values.

Enter a number or expression for all variables except the one you want to solve for.

The solution must be within the specified bounds, which you can edit.

Notes and Common Errors

• If you define a variable:
  • In terms of another variable in the equation, that variable must be defined first.
  • In terms of another variable that is not in the equation, that variable must already have a value; it cannot be undefined.
  • As an expression, it is evaluated when you move the cursor off the line. The expression must evaluate to a real number.

Since a is defined in terms of g, you must define g before a. When you move the cursor to another line, g/3 is evaluated.

Note: When you assign a value to a variable in the Numeric Solver, that variable is defined globally. It still exists after you leave the solver.

• If the equation contains a variable already defined in terms of other variables, those other variables are listed.

If variable a was defined previously as b+c>a, then b and c are listed instead of a.

• If you refer to a previously defined function, any variables used as arguments in the function call are listed, not the variables used to define the function.

If f(a,b) was defined previously as \sqrt(a^2+b^2) and your equation contains f(x,y), then x and y are listed, not a and b.

Chapter 19: Numeric Solver 337

Note: You cannot solve for a system variable other than exp. Also, if the equation contains a system variable, you cannot use F3 to graph.

Note: This error occurs if you use a reserved name incorrectly or refer to an undefined system function as a simple variable without parentheses.

• If the equation contains a system variable (xmin, xmax, etc.), that variable is not listed. The solver uses the system variable’s existing value. In the standard viewing window, xmax=10.

• Although you can use a system variable in the equation, an error occurs if you use F3 to graph the solution.

• If you see the error shown to the right, delete the entered variable value. Then edit the equation to use a different variable. For example, y1(x) is undefined and you use y1.

Editing the Equation

In the Numeric Solver, press \odot until the cursor is on the equation. The screen automatically changes to show only the eqn: line. Make your changes, and then press ENTER or \odot to return to the list of variables.

Specifying an Initial Guess and/or Bounds (Optional)

Tip: To select an initial guess graphically, refer to pages 340 and 341.

To find a solution more quickly or to find a particular solution (if multiple solutions exist), you can optionally:

• Enter an initial guess for the unknown variable. The guess must be within the specified bounds. Initial guess must be within the bounds.

• Enter lower and upper bounds close to the solution.

For the bounds, you can also enter variables or expressions that evaluate to appropriate values (bound=(lower,upper)) or a valid list variable that contains a two-element list (bound=list). The bounds must be two floating point elements with the first one less than or equal to the second one.

338 Chapter 19: Numeric Solver

Solving for the Unknown Variable

After you type an equation in the Numeric Solver and enter values for the known variables, you are ready to solve for the unknown variable.

Finding the Solution

With all known variables defined:

1. Move the cursor to the unknown variable.
2. Press F2 Solve.

A ■ marks the solution and left–rt. The ■ disappears when you edit a value, move the cursor to the equation, or leave the solver.

Using the solution and your entered values, the left and right sides of the equation are evaluated separately. left–rt shows the difference, which indicates the solution’s accuracy. The smaller the value, the more accurate the solution. If the solution is precise, left–rt=0.

Note: To stop (break) a calculation, press ON. The unknown variable shows the value being tested when the break occurred.

\begin{tabular}{ll} If you: & Do this: \ Want to solve for other & Edit the equation or variable values. \ values & \ Want to find a different & Enter an initial guess and/or a new set of \ solution for an equation & bounds close to the other solution. \ with multiple solutions & \ See the message: & Press ESC. The unknown variable shows \ & the value being tested when the error \ & occurred. \ & \textbullet{} The left–rt value may be small enough \ & for you to accept the result. \ & \textbullet{} If not, enter a different set of bounds. \ \end{tabular}

Note: An iterative process is used to solve an equation. If the iterative process cannot converge on a solution, this error occurs.

Chapter 19: Numeric Solver 339

Graphing the Solution

You can graph an equation’s solutions any time after defining the known variables, either before or after you solve for the unknown variable. By graphing the solutions, you can see how many solutions exist and use the cursor to select an accurate initial guess and bounds.

Displaying the Graph

In the Numeric Solver, leave the cursor on the unknown variable. Press F3 and select:

1:Graph View – or – 3:ZoomStd – or – 4:ZoomFit

Graph View uses the current Window variable values.

For information about ZoomStd and ZoomFit, refer to Chapter 6.

Tips: With split screens:

• Use [2nd] [↔] to switch between sides.
• The active side has a thick border.
• The toolbar belongs to the active side.

For more information, refer to Chapter 14.

The graph is shown in a split screen, where:

• The unknown variable is plotted on the x axis.
• left-rt is plotted on the y axis.

Solutions for the equation exist at left-rt=0, where the graph crosses the x axis.

The current graph format settings are used.

You can explore the graph by using the free-moving cursor, tracing, zooming, etc., as described in Chapter 6.

How the Graph Affects Various Settings

When you use the Numeric Solver to display a graph:

• The following modes are changed automatically to these settings:

Note: If you were previously using different mode settings, you will need to reselect those settings manually.

\begin{tabular}{ll} Mode & Setting \ Graph & FUNCTION \ Split Screen & LEFT-RIGHT \ Number of Graphs & 1 \ \end{tabular}

Any functions selected in the Y= Editor will not be graphed.

• All stat plots are deselected.
• After you leave the Numeric Solver, the Graph screen may continue to display the equation's solution, ignoring any selected Y= functions. If so, display the Y= Editor and then return to the Graph screen. Also, the graph is reset when you change the Graph mode or use ClrGraph from the Home screen ([F4] 5) or a program.

340 Chapter 19: Numeric Solver

Selecting a New Initial Guess from the Graph

To use the graph cursor to select an initial guess:

1. Move the cursor (either free-moving or trace) to the point that you want to use as the new guess.
2. Use 2nd [ZOOM] to make the Numeric Solver screen active.
3. Make sure the cursor is on the unknown variable, and press F4.
4. Press F2 to re-solve the equation.

Note: Cursor coordinate xc is the unknown variable value, and yc is the left-rt value.

F4 sets the graph cursor's xc value as an initial guess and the yc value as left-rt. The graph's xmin and xmax values are set as the bounds.

Returning to a Full Screen

From the split screen:

• To display the Numeric Solver full screen, use 2nd [ZOOM] to make the solver screen active, press F3, and then select 2:Clear Graph View. – or –
• To display the Home screen, press 2nd [QUIT] twice.

Clearing Variables Before Leaving the Numeric Solver

When you solve an equation, its variables still exist after you leave the Numeric Solver. If the equation contains single-character variables, their values may inadvertently affect later symbolic calculations. Before leaving the Numeric Solver, you may want to:

Tip: Any time you want to clear single-character variables listed in the solver, use: TI-89: 2nd F6 TI-92 Plus: F6

1. Press: TI-89: 2nd F6 TI-92 Plus: F6 to clear all single-character variables in the current folder.
2. Press ENTER to confirm the action.

The screen returns to the solver's eqn: line.

Chapter 19: Numeric Solver 341

342 Chapter 19: Numeric Solver

Number Bases

20

• Preview of Number Bases ........ 344
• Entering and Converting Number Bases ........ 345
• Performing Math Operations with Hex or Bin Numbers ........ 346
• Comparing or Manipulating Bits ........ 347

Note: The MATH/Base menu lets you select from a list of operations related to number bases.

Wherever you enter an integer in a TI-89 / TI-92 Plus calculation, you can enter it in decimal, binary, or hexadecimal form. You can also set the Base mode to specify the form for displaying integer results. Fractional and floating-point results are always displayed in decimal form.

Binary numbers use 0 and 1 in the base 2 format:

100
|— 2⁰ * 0 = +0
|— 2¹ * 0 = +0
|— 2² * 1 = +4

Hexadecimal numbers use 0 – 9 and A – F in the base 16 format:

A8F
|— 16⁰ * F = +15
|— 16¹ * 8 = +128
|— 16² * A = +2560

You can use the TI-89 / TI-92 Plus to convert a number from one base to another. For example, 100 binary = 4 decimal and A8F hex = 2703 decimal.

Hexadecimal numbers are often used as a shorthand notation for longer, hard-to-remember binary numbers. For example:

1010 1111 0011 0111
A F 3 7

AF37 hexadecimal is usually easier to work with than 1010111100110111 binary.

The TI-89 / TI-92 Plus also lets you compare or manipulate binary numbers bit-by-bit.

Chapter 20: Number Bases 343

Preview of Number Bases

Calculate 10 binary (base 2) + F hexadecimal (base 16) + 10 decimal (base 10). Then, use the ▶ operator to convert an integer from one base to another. Finally, see how changing the Base mode affects the displayed results.

344 Chapter 20: Number Bases

Entering and Converting Number Bases

Regardless of the Base mode, you must always use the appropriate prefix when entering a binary or hexadecimal number.

Entering a Binary or Hexadecimal Number

To enter a binary number, use the form:

0b\textitbinaryNumber (for example: 0b11100110)

• Binary number with up to 32 digits
• Zero, not the letter O, and the letter b

Note: You can type the b or h in the prefix, as well as hex characters A – F, in uppercase or lowercase.

To enter a hexadecimal number, use the form:

0h\textithexadecimalNumber (for example: 0h89F2C)

• Hexadecimal number with up to 8 digits
• Zero, not the letter O, and the letter h

If you enter a number without the 0b or 0h prefix, such as 11, it is always treated as a decimal number. If you omit the 0h prefix on a hexadecimal number containing A – F, all or part of the entry is treated as a variable.

Converting between Number Bases

Use the \blacktriangleright conversion operator.

\textitintegerExpression \blacktriangleright Bin \textitintegerExpression \blacktriangleright Dec \textitintegerExpression \blacktriangleright Hex

For \blacktriangleright, press [2nd] [\blacktriangleright]. Also, you can select base conversions from the MATH/Base menu.

Note: If your entry is not an integer, a Domain error is displayed.

For example, to convert 256 from decimal to binary:

256 \blacktriangleright Bin

To convert 101110 from binary to hexadecimal:

0b101110 \blacktriangleright Hex

Results use the 0b or 0h prefix to identify the base.

Alternate Method for Conversions

Instead of using \blacktriangleright, you can:

1. Use [MODE] (page 346) to set the Base mode to the base that you want to convert to.
2. From the Home screen, type the number that you want to convert (using the correct prefix) and press [ENTER].

If Base mode = BIN:

If Base mode = HEX:

Chapter 20: Number Bases 345

Performing Math Operations with Hex or Bin Numbers

For any operation that uses an integer number, you can enter a hexadecimal or binary number. Results are displayed according to the Base mode. However, results are restricted to certain size limits when Base = HEX or BIN.

Setting the Base Mode for Displayed Results

1. Press MODE F2 to display Page 2 of the MODE screen.
2. Scroll to the Base mode, press ( ), and select the applicable setting.
3. Press ENTER to close the MODE screen.

Note: The Base mode affects output only. You must always use the 0h or 0b prefix to enter a hex or binary number.

The Base mode controls the displayed format of integer results only.

Fractional and floating-point results are always shown in decimal form.

If Base mode = HEX:

0h prefix in result identifies the base.

Dividing When Base = HEX or BIN

When Base=HEX or BIN, a division result is displayed in hexadecimal or binary form only if the result is an integer.

To ensure that division always produces an integer, use intDiv() instead of \div.

If Base mode = HEX:

Press [ ] ENTER] to display the result in APPROXIMATE form.

Size Limitations When Base = HEX or BIN

When Base=HEX or BIN, an integer result is stored internally as a signed, 32-bit binary number, which uses the range (shown in hexadecimal and decimal):

If a result's magnitude is too large to be stored in a signed, 32-bit binary form, a symmetric modulo operation brings the result into the range. Any number greater than 0h7FFFFFFF is affected. For example, 0h80000000 through 0hFFFFFFFF become negative numbers.

346 Chapter 20: Number Bases

Comparing or Manipulating Bits

The following operators and functions let you compare or manipulate bits in a binary number. You can enter an integer in any number base. Your entries are converted to binary automatically for the bitwise operation, and results are displayed according to the Base mode.

Boolean Operations

Note: You can select these operators from the MATH/Base menu. For an example using each operator, refer to Appendix A in this book.

Suppose you enter:
0h7AC36 and 0h3D5F

Internally, the hexadecimal integers are converted to a signed, 32-bit binary number. Then corresponding bits are compared.

If Base mode = HEX:
■ 0h7AC36 and 0h3D5F 0h2C16 0h7ac36 and 0h3d5f MAIN RAD AUTO FUNC □/□□

If Base mode = BIN:
■ 0h7AC36 and 0h3D5F 0b10110000010110 0h7ac36 and 0h3d5f MAIN RAD AUTO FUNC □/□□

Note: If you enter an integer that is too large to be stored in a signed, 32-bit binary form, a symmetric modulo operation brings the value into the range (page 346).

0h7AC36 = 0b00000000000001111010110000110110 and and 0h3D5F = 0b000000000000000000111101011111 0b00000000000000000001011000010110 = 0h2C16 ______ Leading zeros are not shown in the result.

The result is displayed according to the Base mode.

Chapter 20: Number Bases 347

Rotating and Shifting Bits

Note: You can select these functions from the MATH/Base menu. For an example using each function, refer to Appendix A in this book.

Function with syntax

rotate(integer)
– or –
rotate(integer,#ofRotations)

Description

If #ofRotations is:

• omitted — bits rotate once to the right (default is -1).
• negative — bits rotate the specified number of times to the right.
• positive — bits rotate the specified number of times to the left.

In a right rotation, the rightmost bit rotates to the leftmost bit; vice versa for a left rotation.

Function with syntax

shift(integer)
– or –
shift(integer,#ofShifts)

Description

If #ofShifts is:

• omitted — bits shift once to the right (default is -1).
• negative — bits shift the specified number of times to the right.
• positive — bits shift the specified number of times to the left.

In a right shift, the rightmost bit is dropped and 0 or 1 is inserted to match the leftmost bit. In a left shift, the leftmost bit is dropped and 0 is inserted as the rightmost bit.

Suppose you enter:
shift(0h7AC36)

Internally, the hexadecimal integer is converted to a signed, 32-bit binary number.

Then the shift is applied to the binary number.

If Base mode = HEX:

■ shift(0h7AC36) 0h3D61B shift(0h7ac36) MAIN RAD AUTO FUNC □/□□

If Base mode = BIN:

■ shift(0h7AC36) 0b111101011000011011 shift(0h7ac36) MAIN RAD AUTO FUNC □/□□

Note: If you enter an integer that is too large to be stored in a signed, 32-bit binary form, a symmetric modulo operation brings the value into the range (page 346).

0h7AC36 = 0b000000000000001111010110000110110 ↑ ↓ Inserts 0 if leftmost bit is 0, Dropped or 1 if leftmost bit is 1. ↗ Each bit shifts to the right.

0b000000000000000111101011000011011 = 0h3D61B ↖___________________________ Leading zeros are not shown in the result.

The result is displayed according to the Base mode.

348 Chapter 20: Number Bases

Memory and Variable Management

21

• Preview of Memory and Variable Management ........ 350
• Checking and Resetting Memory ........ 353
• Displaying the VAR-LINK Screen ........ 355
• Manipulating Variables and Folders with VAR-LINK ........ 357
• Pasting a Variable Name to an Application ........ 359
• Archiving and Unarchiving a Variable ........ 360
• If a Garbage Collection Message Is Displayed ........ 362
• Memory Error When Accessing an Archived Variable ........ 364

This chapter describes how to manage variables stored in the TI-89 / TI-92 Plus’s memory.

Note: Remember that variables can contain expressions, lists, functions, programs, graph figures, etc.

Note: You can also use VAR-LINK to transfer variables between two linked TI-89s, a TI-92, or a TI-92 Plus. Refer to Chapter 22.

The MEMORY screen shows how the memory is currently being used.

The VAR-LINK screen displays a list of defined variables and folders. For information about folders, refer to Chapter 5.

You can also store variables in the TI-89 / TI-92 Plus’s user data archive, a protected area of memory separate from RAM (random access memory).

You can archive and unarchive a variable.

Archiving variables can be very useful (page 360). However, if you do not need the benefits of the user data archive, you do not need to use it.

Chapter 21: Memory and Variable Management 349