EC-4044 (650-0808) Understanding the Keyboard Faxback Doc. # 3572 To make the most of the EC-4044 keyboard, almost every key has more than one purpose. The primary function of a key is marked on the lower half of the key. Other purposes of the key are marked higher on the key or above the key. Some functions also have an inverse function. Replacing or When you have begun a second or third function, you can Cancelling an replace 2nd with 3rd or 3rd with 2nd. Alternate Function When you have begun a hyperbolic or alpha function, you can replace HYP with ALPHA or ALPHA with HYP. If you accidentally press an undesired alternate function key such as 2nd, you can easily cancel it. To cancel, press the key again. If you select an alternate function and press a key for which that alternate function does not apply, the key accesses the primary function. For instance, HYP LOG is the same as LOG. Combined INV can be combined with 2nd, 3rd, or HYP to access the Alternate inverses of certain alternate functions. You can press Functions INV before or after 2nd, 3rd, or HYP. Either order selects the same combined alternate function. If you select a combined alternate function and press a key for which neither alternate function applies, the key accesses the primary function. For instance, INV HYP/ is the same as /. If you select a combined alternate function and press a key for which only one of the alternate functions apply, the key ignores the alternate function that does apply. For instance, INV 2nd [pie SYMBOL] is the same as 2nd [pi SYMBOL]. If you select alpha combined with 2nd or 3rd, and press a key for which both of the alternate functions apply, the key ignores the alpha selection and accesses the 2nd or 3rd function. For instance, ALPHA 2nd [x!] is the same as 2nd [x!]. Representation Many of the functions are abbreviated differently on of a Function the keyboard than they are in the display. -> As a key label, a function needs to appear in its most eye-catching form, enabling you to find a function quickly when scanning the keyboard. -> As a displayed item, a function needs to be distinguishable from a variable, enabling you to interpret the display with greater clarity. The difference is often the capitalization of the abbreviation. Entering Numbers and Calculations This chapter presents the features that you use to enter numbers and to perform calculations. Number Entry Options When you enter a number, you can include accompanying symbols along with the digits. The digits and symbols together form a number for the calculator to interpret. Before You The calculator is ready for you to enter a new problem Begin a New after you press =/ENTER to execute a calculation. You Calculation do not need to clear the display unless you wish to discard an entry that you have begun but not executed. To clear the display line, press CLEAR. This key has no effect on stored values, formulas, or the statistics data set. Digits of an The number base of an entry determines the digits that Entry are valid for that entry. -> A decimal (base ten) entry can consist of the digits 0 through 9. -> Entries for the other number bases (hexadecimal, octal, and binary) have different sets of digits, which are presented in Chapter 9. Symbols That Along with the digits of a number, you can include Can Accompany symbols to modify the meaning of the number. These Digits in a symbols remain part of the number even if you store it Number in memory. The settings the calculator has for the appearance of results do not affect the types of numbers you can enter. -> To make the number negative, place a minus symbol ahead of the number using the (-) key (which is different from the subtraction key -). Negation is explained in detail on the next page. -> To enter the number as degrees, minutes, and seconds, punctuate the number using the DMS key. This feature is presented in Chapter 3. -> To pair two numbers as the parts of a complex number, use parentheses and the comma or angle separator. This feature is presented in Chapter 4. -> To designate that a number is in a specific number base, include the symbol for decimal (d), hexadecimal (h), octal (o), or binary (b) just after the number. This feature is presented in Chapter 9. The Negation The effect of the negation symbol depends on how it is Function used in an entry. You can place a "-" ahead of: -> A number or exponent of scientific notation. The number or exponent becomes negative. -> A variable, a recalled number, a statistics result, or pi. The value becomes negative. -> A function that belongs ahead of a number or an open parenthesis. The negation function will be performed when the entry is executed. Entering a Scientific To enter a number in scientific notation: Notation 1. If the number is negative, press (-). 2. Type the part of the number that belongs before the exponent (often called the mantissa), up to 13 digits. Include the decimal where appropriate. 3. Press EE. An E appears in the display. This E is smaller than the alpha E or the hex digit E. 4. If the exponent is negative, press (-). 5. Type one or two digits for the exponent. Entering a number in scientific notation does not cause the results to be shown in scientific notation.. The notation used for results depends on the setting that you adjust with 3rd [ScEn>] and the ability of the result to fit in 10 digits. The Number Pi Instead of entering the digits of pi separately, you can use the 2nd (pi SIGNAL) key sequence to place the Pie symbol in the display. Internally, the 13-digit value for pi (3.141592653590) is used. Variables You can use a variable in place of a number. This feature is described in Chapter 5. Entry Terminology and Capacities The entry line is longer than the visible display. You can consider the display as a window showing 12 characters of the entry. An entry that has more than 12 characters goes beyond the display. The calculator has features to help you recognize when an entry is nearing the capacity of the entry line. Entry Length A decimal number can have up to 13 digits and two exponent digits (13 digits and two exponent digits for each part of a complex number). A number in DMS format can have up to nine digits. A hexadecimal, octal, or binary number can have up to 10 digits. Along with the numbers, an entry consists of functions and operations of the expression. Each digit or symbol (such as a comma or decimal point) in a number is considered to be an item in the entry. Each letter of a variable name is also one item. However, a function or operation is just one item even though it appears to have more than one character. For example, log is one item even though it has three characters. You can think of the terms "equation " and "formula" as specific cases of the more general term, expression. -> Equation - an expression that you enter for temporary use. An equation can have up to 80 items. -> Formula - an expression that you save for later use. You name each formula before you enter it. A formula can have up to 79 items. When you are approaching the length limit, the cursor changes from an underline to a box after the 70th item. When your expression reaches the length limit, any key that would place another item in the display is ignored. Note that your entry can approach the length limit even though you may not be at the end of the entry line. You can also reach the length limit while: -> Inserting items within an expression. -> Recalling a number within an expression, which inserts the individual digits and symbols of the number. Reviewing a You can look for arrow indicators near the upper Long Entry corners of the display to determine whether an entry goes past the display. If <- appears, more of the entry is to the left of the display. If -> appears, more of the entry is to the right of the display. To review a long entry before executing it, scroll the entry by pressing the <- and -> keys. <- shifts the cursor to the left and -> shifts the cursor to the right. These keys automatically repeat when held down. (br/all-12/12/94)