Chapter One
Coping with the Basics
In This Chapter
* Turning the calculator on and off
* Using the keyboard
* Using the menus
* Setting the mode of the calculator
* Using the Catalog
The TI-84 graphing calculator is loaded with many useful features. With them, you can construct and investigate geometric figures. You can graph and investigate functions, parametric equations, polar equations, and sequences. You can use them to analyze statistical data and to manipulate matrices. You can even use them to calculate mortgage payments.
But if you've never used a graphing calculator before, you may at first find it a bit intimidating. After all, it contains about two dozen menus, many of which contain three or four submenus. But it's really not that hard to get used to using the calculator. After you get familiar with what the calculator is capable of doing, finding the menu that houses the command you need is quite easy. And you have this book to help you along the way.
When to Change the Batteries
The convenience of battery power has a traditional downside: What if the batteries run out of juice at a crucial moment, say during a final exam? Fortunately, the calculator gives you some leeway. When your batteries are low, the calculator displays a "Your batteries are low" warning message. After you see this message for the first time, the calculator should, according to the manufacturer, continue to function just fine for at least one week. There is one exception: If you attempt to download an application when the batteries are low, the calculator displays a "Batteries are low - Change is required" warning message and refuses to download the application until after you've changed the batteries. (Chapter 18 explains how to download applications.)
Because you've likely put batteries into countless toys, you should have no trouble opening the cover on the back of the calculator and popping in four AAA batteries. Above the AAA battery chamber is a panel that opens to the compartment containing the backup battery. The type of battery housed in this compartment is indicated on the lid of the panel. The manufacturer recommends that you replace this battery every three or four years. So mark your calendar!
Turning the Calculator On and Off
Press [ON] to turn the calculator on. To turn the calculator off, Press [2nd], and then press [ON]. These keys are in the left column of the keyboard. The [ON] key is at the bottom of the column, and the [2nd] key is the second key from the top of this column.
To prolong the life of the batteries, the calculator automatically turns itself off after five minutes of inactivity. But don't worry - when you press [ON], all your work will appear on the calculator just as you left it before the calculator turned itself off.
In some types of light, the screen can be hard to see. To increase the contrast, press and release [2nd] and then hold down [arrow up] until you have the desired contrast. To decrease the contrast, press [2nd] and hold [arrow down].
Using the Keyboard
The row of keys under the calculator screen contains the keys you use when graphing. The next three rows, for the most part, contain editing keys, menu keys, and arrow keys. The arrow keys ([right arrow][left arrow][up arrow][down arrow]) control the movement of the cursor. The remaining rows contain, among other things, the keys you typically find on a scientific calculator.
REMEMBER
Keys on the calculator are always pressed one at a time; they are never pressed simultaneously. In this book, an instruction such as [2nd][ON]indicates that you should first press [2nd] and then press [ON].
Accessing the functions in blue
Above and to the left of most keys is a secondary key function written in blue. To access that function, first press [2nd] and then press the key. For example, [pi] is in blue above the [^] key, so to use [pi] in an expression, press [2nd] and then press [^].
Because hunting for the function in blue can be tedious, in this book I use only the actual keystrokes. For example, I will make statements like, "[pi] is entered into the calculator by pressing [2nd] [^]" Most other books would state, "[pi] is entered into the calculator by pressing [2nd][pi]."
TIP
When the [2nd] key is active and the calculator is waiting for you to press the next key, the blinking [??] cursor symbol is replaced with the [up arrow] symbol.
Using the [ALPHA] key to write words
Above and to the right of most keys is a letter written in green. To access these letters, first press [ALPHA] and then press the key. For example, because the letter O is in green above the [7] key, to enter this letter, press [ALPHA] and then press [7].
Because hunting for letters on the calculator can be tedious, I tell you the exact keystrokes needed to create them. For example, if I want you to enter the letter 0, I say, "Press [ALPHA][7] enter the letter 0." Most other books would say "Press [ALPHA] [0]" and leave it up to you to figure out where that letter is on the calculator.
TIP
You must press [ALPHA] before entering each letter. However, if you want to enter many letters, first press [2nd][ALPHA] to lock the calculator in Alpha mode. Then all you have to do is press the keys for the various letters. When you're finished, press [ALPHA] to take the calculator out of Alpha mode. For example, to enter the word TEST into the calculator, press [2nd][ALPHA][4][SIN][LN][4] then press [ALPHA] to tell the calculator that you're no longer entering letters.
TIP
When the calculator is in Alpha mode, the blinking [??] cursor symbol is replaced with the [A] symbol. This symbol indicates that the next key you press will insert the green letter above that key. To take the calculator out of Alpha mode, press [ALPHA].
Using the [ENTER] key
The [ENTER] key is used to evaluate expressions and to execute commands. After you have, for example, entered an arithmetic expression (such as 5 + 4), press [ENTER] to evaluate that expression. In this context, the [ENTER] key functions as the equal sign. Entering arithmetic expressions is explained in Chapter 2.
Using the [X,T, [??], n]key
[X,T, [??]n]is the key you use to enter the variable in the definition of a function, a parametric equation, a polar equation, or a sequence. In Function mode, this key produces the variable X. In Parametric mode it produces the variable T; and in Polar and Sequence modes it produces the variables [theta] and n, respectively. Setting the mode is explained later in this chapter.
Using the arrow keys
The arrow keys ([right arrow],[left arrow],[up arrow], and [down arrow ]) control the movement of the cursor. These keys are in a circular pattern in the upper-right corner of the keyboard. As expected, [right arrow] moves the cursor to the right, [left arrow] moves it to the left, and so on. When I want you to use the arrow keys - but not in any specific order - I refer to them all together, as in "Use [right arrow][left arrow][up arrow][down arrow] to place the cursor on the entry."
What Is the Home Screen?
The Home screen is the screen that appears on the calculator when you first turn it on. This is the screen where most of the action takes place as you use the calculator - it's where you evaluate expressions and execute commands. This is also the screen you usually return to after you've completed a task such as entering a matrix in the Matrix editor or entering data in the Stat List editor.
REMEMBER
Press [2nd][MODE]to return to the Home screen from any other screen. This combination of keystrokes, [2nd][MODE], is the equivalent of the Escape key on a computer. It always takes you back to the Home screen.
REMEMBER
If you want to clear the contents of the Home screen, repeatedly press [CLEAR] until the Home screen is blank.
The Busy Indicator
If you see a moving vertical line in the upper-right corner of the screen, this indicates that the calculator is busy graphing a function, evaluating an expression, or executing a command.
TIP
If it's taking too long for the calculator to graph a function, evaluate an expression, or execute a command, and you want to abort the process, press [ON]. If you're then confronted with a menu that asks you to select either Quit or Goto, select Quit to abort the process.
Editing Entries
The calculator offers four ways to edit an entry:
[Check] Deleting the entire entry:
Use [right arrow][left arrow][up arrow][down arrow] to place the cursor anywhere in the entry and then press [CLEAR] and to delete the entry.
[Check] Erasing part of an entry:
To erase a single character, use [right arrow][left arrow][up arrow][down arrow] to place the cursor on the character you want to delete and then press [DEL] to delete that character.
[Check] Inserting characters:
Because "typing over" is the default mode, to insert characters you must first press [2nd][DEL]to enter Insert mode. When you insert characters, the inserted characters are placed to the left of the cursor. For example, if you want to insert CD between B and E in the word ABEF, you would place the cursor on E to make the insertion.
To insert characters, use [right arrow][left arrow][up arrow][down arrow] to place the cursor at the location of the desired insertion, press [2nd][DEL], and then key in the characters you want to insert. When you're finished inserting characters, press one of the arrow keys to take the calculator out of Insert mode.
[Check] Keying over existing characters:
"Type over" is the default mode of the calculator. So if you want to overtype existing characters, just use [right arrow][left arrow][up arrow][down arrow] to put the cursor where you want to start, and then use the keyboard to enter new characters.
TIP
On the Home screen, the calculator doesn't allow you to directly edit an already-evaluated expression or an already-executed command. But you can recall that expression or command if it was the last entry you made in the calculator - and when it's recalled, you can edit it. To recall the last expression or command, press [2nd][ENTER]. This makes the calculator paste a copy of the desired expression or command on the Home screen so you can edit it.
Using Menus
Most functions and commands you use are found in the menus housed in the calculator - and just about every chapter in this book refers to them. This section is designed to give you an overview of how to find and select menu items.
Accessing a menu
Each menu has its own key or key combination. For example, to access the Math menu, press [MATH]; to access the Test menu, press [2nd][MATH]. An example of a menu appears in the first picture in Figure 1-1. This is a picture of the Math menu.
Some menus, such as the Math menu, contain submenus. This is also illustrated in the first picture in Figure 1-1. This picture shows that the submenus in the Math menu are MATH, NUM, CPX, and PRB (Math, Number, Complex, and Probability). Repeatedly press [right arrow] to view the items on the other submenus; repeatedly press [left] to return to the Math MATH submenu. This is illustrated in the second and third pictures in Figure 1-1.
Scrolling a menu
After the number 7 in the first two pictures in Figure 1-1, a down arrow indicates that more items are available in the menu than appear on-screen. There's no down arrow after the 7 in the third picture in Figure 1-1 because that menu has exactly seven items.
To see menu items that don't appear on-screen, repeatedly press [down arrow]. To get quickly to the bottom of a menu from the top of the menu, press [up arrow]. Similarly, to quickly get from the bottom to the top, press [down arrow].
Selecting menu items
To select a menu item from a menu, key in the number (or letter) of the item or use [down arrow] to highlight the number (or letter) of the item and then press [ENTER].
Some menus, such as the Mode menu that is pictured in Figure 1-2, require that you select an item from a list of items by highlighting that item. The list of items usually appear in a single row and the calculator requires that one item in each row be highlighted. To highlight an item, use [right arrow][left arrow][up arrow][down arrow] to place the cursor on the item and then press [ENTER] to highlight the item. The selections on the Mode menu are described in the next section.
Setting the Mode
The Mode menu, which is accessed by pressing [MODE], is the most important menu on the calculator; it tells the calculator how you want numbers and graphs to be displayed. The Mode menu is pictured in Figure 1-2.
(Continues...)
Excerpted from TI-84 Plus Graphing Calculator For Dummies by C.C. Edwards Excerpted by permission.
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