HP 38g User Manual

User's Guide

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aplet views

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for entering

Alpha shift

shift key (turquoise)

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LI VIEWS NOTE SKETCH

_____

1 1 MODES ASIN ACOS ATAN x-1

1 1

1 1 ANSWER CHARS EEX

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CLEAR NOTEPAD SPACE K LN

OFF PROGRAM

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CANCEL

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MATRIX [

1 ■ 2 I 3

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5 ■ 6 ■ ^

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The {{ok}} menu-key

label (when present in the display) acts the same as the | enter]

key.

Key Conventions-Examples:

■ [ANSWER] Means press the shift key followed by the | enter] key.

|a...z|A Means press the Alpha-shift key followed by the | home | key.

HP 38G Graphing Calculator

User’s Guide

HEWLETT®

PACKARD

HP Part No. FI 200-90013

Printed in Singapore

Notice

This manual and any examples contained herein are provided “as is” and are subject to change without notice. Hewlett-Packard Company makes no warranty of any kind with regard to this manual, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Hewlett-Packard Co. shall not be liable for any eiTors or for incidental or consequential damages in connection with the furnishing, performance, or use of this manual or the examples herein.

© Copyright Hewlett-Packard Company 1995. All rights reserved. Reproduction, adaptation, or translation of this manual is prohibited without prior written permission of Hewlett-Packard Company, except as allowed under the copyright laws.

The programs that control this product are copyrighted and all rights are reserved. Reproduction, adaptation, or translation of those programs without prior written permission of Hewlett-Packard Co. is also prohibited.

Hewlett-Packard Co. Australian Calculator Operation 347, Burwood Highway Burwood East Victoria 3151 Australia

Acknowledgments

Hewlett-Packard gratefully acknowledges the members of the Education Advisory Committee (Walter Bitz, Tom Dick, Mark Howell, Alice Kaseberg, Jim McManus, Carla Randall, Alison Warr, and Wade White) for their assistance in the development of this product.

Edition History

Edition 2

...............

.January 1998

Getting Started

Starting Out...........................................................................1-1

The Keyboard

The Display.............................................................................1-6

Display Modes Using Input Forms

Home History......................................................................1-9

Menu Lists........................................................................ 1-10

Aplets and Their Views.......................................................1-11

Aplets.................................................................................1-11

Views..................................................................................1-12

Exploring an Aplet View by View

Catalogs and Editors...........................................................1-16

Storing and Recalling Variables Notes and Sketches

Note View and Sketch View

The Notepad......................................................................1-23

Managing Aplets....................................................................1 -25

Sending and Receiving Aplets

Mathematical Calculations

How to Do Calculations........................................................2-1

Entering Expressions.........................................................2-1

Complex Numbers..............................................................2-4

Clearing Numbers..............................................................2-4

Using Previous Results.......................................................2-4

Storing in Variables...............................................................2-6

The VAR Menu......................................................................2-7

Symbolic Calculations

Using Math Functions.........................................................2-12

The MATH Menu.............................................................2-12

The Math Functions by Category...................................2-13

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1-2

1-7 1-8

1 -14

1-17 1-18 1-18

1-27

2-10

Contents-1

Plotting and Exploring Functions

Defining a Problem

Select an Aplet

Define an Expression (Symbolic View)............................3-2

Evaluating Expressions Examples: Defining Expressions

Plotting....................................................................................3-7

Plot the Expression (Plot View) Examples: Plotting

Exploring the Plot

Tracing

..............................................................................

Zooming.............................................................................3-13

Other Views for Scaling and Splitting the Graph

Setting Up the Plot (Plot Setup)

Interactive Root-Finding Examples: Root-Finding with Plots

Using a Table of Numbers

Display a Table of Numbers (Numeric View) Exploring the Table of Numbers

Setting Up the Table (Numeric Setup)

Building Your Own Table of Numbers..........................3-26

More Examples

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Solve

Solving Equations..................................................................4-2

Define the Equation

Solve for the Unknown Variable Plotting the Equation

Interpreting Results...............................................................4-7

Plotting to Find Guesses........................................................4-8

About Variables...................................................................4-11

...........................................................

......................................

............................................................

3-1

3-2

3-5 3-6

3-7

3-8 3-11 3-12

3-16 3-18 3-19 3-21 3-23 3-23 3-24 3-25

3-28

4-2 4-4 4-6

Contents-2

Statistics

Example: Finding a Linear Equation to Fit Data

Entering Statistical Data.......................................................5-5

One-Variable Data

Two-Variable Data.............................................................5-9

Managing Statistical Data

Analyzing the Data

Defining a Regression Model (2VAR)............................5-14

Computing Statistics (IVAR and 2VAR)

Plotting..................................................................................5-19

Plot Types..........................................................................5-20

Fitting a Curve to 2VAR Data........................................5-21

Regression Coefficients Plot Settings Trouble-shooting

Exploring the Plot................................................................5-23

Calculating Predicted Values..........................................5-24

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Using Matrices

Creating and Storing Matrices

Matrix Arithmetic..................................................................6-6

Solving Systems of Linear Equations

Matrix Functions....................................................................6-9

Examples...........................................................................6-13

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...............................

5-2

5-6

5-12 5-14

5-16

5-21 5-22 5-22

6-1

6-8

Using Lists

Creating and Storing Lists

List Functions.........................................................................7-4

Finding Statistical Values for List Elements

...................................................

...................

7-1

7-7

Contents-3

Programming

The Contents of a Program...............................................8-1

Structured Programming

Using the Program Catalog..................................................8-1

Programming Commands

Aplet Commands..............................................................8-10

Branch Commands..........................................................8-11

Drawing Commands

Graphic Commands.........................................................8-15

Loop Commands Matrix Commands Print Commands Prompt Commands

Stat-One and Stat-two Commands.................................8-25

Storing and Retrieving Variables in Programs

The Variable Menu Plot-View Variables Symbolic-View Variables Numeric-View Variables Note Variables

Sketch Variables...............................................................8-39

Menu Maps of the VAR menu.............................................840

Home Variables................................................................8-40

Function Variables...........................................................8-40

Parametric Variables

Polar Vciriables................................................................8-41

Sequence Variables............................................................842

Solve Variables...................................................................842

Statistics Variables

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8-1

8-9

8-13

8-17

8-18

8-20

8-21

8-26

8-28

8-35

8-37

8-39

8-41

843

Reference Information

Regulatory Information........................................................9-1

Limited One-Year Warranty Service

......................................................................................

Batteries..................................................................................9-7

Resetting the HP 38G............................................................9-8

Memory Specifications..........................................................9-8

Glossary..................................................................................9-9

Selected Status Messages....................................................9-11

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Content84

9-3

Getting Started

Read this chapter first! It will get you started using your HP 38G, from turning it on to running aplets.

Starting Out

The Cover The protective cover swivels to provide a base for the

calculator. Be sure to protect the display by replacing the cover before transporting the calculator. Slide the cover gently so as not to hit the keys.

First push the cover away

from you until it

catches.

ON/CANCEL When the calculator is on, the |on| key cancels the current

operation.

OFF

Pressing ■ I ON I (that is, ■ [OFF]) turns the calculator off.

Then swivel the cover to the back and slide it towards you.

Getting Started 1-1

Demo

To see a demonstration of the HP 38G's features, type DEMO

into the edit line in Home. (Press | home | |a...z|D |a...z|E |A...z|M |A...z|0 I ENTER|.) To Stop the demo, press any key.

Home

Power

Home is the calculator’s home base. If you want to do calculations, or you want to quit the current activity (such as an aplet, a program, or an editor), press | home |.

To save power, the calculator turns itself off after several

minutes of inactivity. All stored and displayed information are

saved.

If you see the ((*)) annunciator or the Low Bat message, then the calculator needs fresh batteries. See chapter 9.

The Keyboard

Shifted The ■ (shift) key is a shifted keystroke that accesses the Keystrokes operation printed in turquoise above a key. For instance, to

® access the Modes screen, press ■, then | home |. (You do not

need to hold down the ■ .) This is depicted in this manual as “press ■[MODES] ."

To cancel a shift, press ■ again.

Alpha Shift The alphabetic keys are also shifted keystrokes. For instance,

l^ -^l to type z, press | A...Z | (T|. (The letters are printed in light

green to the lower right of each key.) To cancel Alpha, press | A...Z | again.

• For a lowercase letter, press ■ | A...Z |.

• For a string of letters, hold down | A...Z | while typing.

1-2 Getting Started

Menu Keys You can press fuBl to see this screen;

menu labels

menu keys

« The top-row keys are called menu keys because their

meanings depend on the context—that’s why their tops are blank.

• The bottom line of the display shows the labels for the menu keys’ current meanings, {{save}} is the label for the first menu key in this picture. “Press {{save}}’’ means to press the leftmost top-row key.

Parametric Polar Sequence Solve

Math Keys

Home (press | home |) is the place to do calculations.

• Keyboard keys. The most common arithmetic operations

P256

Getting Started 1-3

MATH menu. The | math | menu is a comprehensive menu

list of math operations that do not appear on the keyboard.

It also includes categories for all other functions and programmable commands. The functions are grouped by category, ranging in alphabetical order from Calculus to

Trigonometry.

Re.3l C CEILING

Stat-Tyo Symbolic

—

Tests ? FNROOT »

BDBSISiaiSI iHamBM

DEG+RFID FLOOR

The arrow keys scroll through the list (Q. ®) ^^d move

from the category list to the item list (0, Q). Press {{cancl}} to cancel the MATH menu. Pressing {{CMDS}} displays the list of Program Commands.

Pressing {{CONS}} displays the list of Program Constants. Pressing {{MTH}} displays the list of Math Functions.

1-4 Getting Started

Keys for Entry

and Editing

Key

(CANCEL)

Meanine

Pressing |ON| while the calculator is on

cancels the current operation. Pressing ■

first turns the calculator off.

■ (shift)

1 HOME 1

[M]

1 ENTER 1 Enters an input or executes an operation. In

[EEX] Enters an exponent of 10. To enter 5x10^

1 x,T,e 1

[MD

■ [CLEAR]

Accesses the function printed in turquoise color above a key.

Home base for calculations.

Alphabetic entry—press before a letter key.

calculations, 1 enter 1 acts like “=“ When

{{OK}} is present as a menu key, | enter] acts

the same as {{OK}}.

Starts a negative number. To enter -5, press 5.

you press 5 ■ [EEX] 9. This appears as

5E9 or, after pressing | enter],

5000000000.

Independent variable key. Types X, T, 0, or N into the display, depending on the current context.

Delete key. Backspaces if at the end of the

line.

Clear key. Clears all data on the screen except settings, which return to their default values.

0 B 0

■ [CHARS] Displays all available characters. To type

Inactive Keys If you press a key that does not operate in the current context,

a warning symbol like this A appears. There is no beep.

Cursor-movement (navigation) keys. Press

■ first to move far.

one, highlight it and press {{OK}}.

Getting Started 1-5

The Display

To adjust the contrast

The Parts of the Display

Annunciators

Simultaneously press decrease) the contrast

6*3

history

edit line

Mmsm

((•))

A T

RAD GRD DEG

8/5

17894

Shift in effect for next keystroke. To cancel, press ■ again.

Alpha in effect for next keystroke. To cancel, press 1 A...Z 1 again.

Low battery power. See chapter 9. Busy. Data is being transferred via infrared or cable.

There is more history in the Home display. Scroll up or down to see it.

Radians angle mode is set for Home. Grads angle mode is set for Home. Degrees angle mode is set for Home.

and 0 (or0) to increase (or

1.6

_ menu-key

labels

To clear the display

• Press

• Press ■ history.

1-6 Getting Started

to clear the edit line.

[CLEAR] to clear the edit line and the display

Display Modes

You can set the Home modes in ^ [MODES]. You make your selections using an input form. To fill out an input form, see “Using Input Forms,” after this table. The Decimal Mark

setting affects all aplets, as well as Home.

When you are done setting MODES, press | home | to return to the Home screen.

[MODES]

Setting

Angle Measure

Number Format

Decimal Mark

Title

Options Angle values are:

Degrees. 360 degrees in a circle. Radians. 2Tr radians in a circle. Grads. 400 grads in a circle.

Standard. Full-precision display.

Fbted. Displays results rounded to a number of decimal places. Example ; 123.456789 becomes

123.4568 in Fixed 4 format.

Scientific. Displays result with an exponent,

one digit to the left of the decimal point, and the specified number of decimal places. Example: 123.456789 becomes 1.23E2 in

Scientific 2 format.

Engineering. Displays result with an exponent that is a multiple of 3, and the specified number of significant digits beyond the first one.

Example: 123.456E7 becomes 1.23E9 in

Engineering 2 format. Fraction. Displays results as fractions based on the specified number of decimal places for

precision. Examples: 123.456789 becomes 123

in Fraction 2 format, and .333 becomes 1/3 and

29/1000 becomes 2/69.

Dot or Comma. Displays a number as 12456.98

(Dot mode) or as 12456,98 (Comma mode).

Dot mode uses commas to separate elements in

lists and matrices, and to separate function

arguments. Comma mode uses periods as separators in these contexts.

Customizes the title in the Home screen.

Getting Started 1-7

To display fractions

Set Fraction mode to display future results as fractions,

1. Press ■ [MODES], then press 0 to select number

FORMAT.

2. Press {{CHOOS}}, highlight Fraction, and press {{OK}}.

3. Press and enter a number for the precision of the fraction. The precision number determines how many

digits appear in the denominator. Press | enter |.

4. Press I HOME I to display Home.

To convert a result to a fraction

1. Set Fraction mode (as in the previous procedure).

2. In Home, press 0 to highlight the number in the history display that you want to convert.

3. Press ((COPY)) lENTERj.

Using Input Forms

An input form shows several fields of information for you to examine and specify. After highlighting the field to edit, you can enter or edit a number (or expression). You can also select options from a list ({{CHOOS}}). Some input forms include items to check ({{/CHK}}).

ANGLE MEASURE: [^PfiifeEH

NUMRER FORMAT; Standard

DECIMAL MARK; Dot < . > TITLE; HOME

CHOOSE ANGLE MEASURE

Example: Change the Angle Measure. Setting Modes

1. Press ■ {MODES} to open the MODES input form.

2. The cursor (highlight) should be on the first line, ANGLE

MEASURE. Press {{CHOOS}} to display a list of choices. Highlight Degrees, Radians, or Grads and press {{OK}}.

HOME MOPES I

3. When done, press | home | to return to Home.

1-8 Getting Started

Hint

Whenever an input form has a list of choices for a field, you can press (T) to cycle through them instead of using

{{CHOOS}}.

To reset values To reset the original, default value in an input form, press

I DEL |. To reset all values in the form, press ■ [CLEAR].

Home History

The Home display (press | home |) shows up to four lines of

history : the most recent input and output. Older lines scroll off the top of the display but are retained in memory; press

m to view them. Note that these examples are in Standard

display mode.

input —

last input-

edit line

— 5*77+4

When you highlight a previous input or result (pressing [Tl) the {{COPY}} and {{show}} menu labels appear. Pressing

{{COPY}} copies the highlighted value to the edit line.

HDME

1.41421356237

HOME

-result

■last result

1.41421356

5*77+1.414213562374

To copy a Highlight the line (press |T|) and press {{COPY}}. The number previous line (or expression) is copied into the edit line.

To repeat a To repeat the very last line, just press ( enter |. Otherwise,

previous line highlight the line (press |T1) first, and then press | enter). The

highlighted expression or number is re-entered.

Getting Started 1-9

To re-use a Press ■ [ANSWER] (last answer) to put the last result from previous result Home into an expression. Ans is a variable that is updated

each time you press [ enter |.

Example See how [ANSWER] retrieves and reuses the last result (50),

and I ENTER I updates Ans (from 50 to 75 to 100).

To display the

full number

Menu Lists

50 I ENTER I 25QH [ANSWER]

25+flns

1 enter! I enter!

You can use the last result as the first expression in the edit

line without pressing ■ [ANSWER]. Pressing 0, 0, or [7], (or other operators that require a preceding argument)

automatically enters Ans before the operator. You can reuse any other expression or value in the Home

display by highlighting the expression (using the arrow keys), then pressing {{copy}}.

If a number or expression is too long to appear on one line, then highlight it (press 0) and press {{SHOW}}. If it is still too long, press [0 to see more. When done, press {{OK}}.

A menu offers you a choice of items. The menu labels across the bottom of some displays are one kind of menu. A menu

list, which appears in one or two columns, is another kind.

FUNCTIONS

Plot-Table Overlay Plot fiuto Scale Decimal

Stat-Two DEG-»RflD Symbolic Tests V FNROOT w

CEILIHG FLOOR

100

• The ▼ arrow in the display means more items below.

• The A arrow in the display means more items above.

1-10 Getting Started

To search a menu list

® Press @ or 0 to scroll through the list. If you press

■ Q or ■ [^, you’ll go all the way to the end or the beginning of the list. Highlight the item you want to select, then press {{OK}} (or | enter |).

• If there are two columns, the left column shows general categories and the right column shows specific contents. Highlight the category on the left, then highlight the item on the right. The list on the right changes when a different category is highlighted. Press {{OK}} or [ enter |.

• To speed-search a list, type the first letter of the word. For example, to find the Matrix category in |math|, press M

(the g key).

• To go up a page, you can press ■ Q- To go down a page, press ■ .

To cancel a menu list

Press CANCEL or {{CANCL}}. This cancels the current

operation.

Aplets and Their Views

Aplets

The HP 38G provides built-in applications to solve specific kinds of math problems. These little applications, or aplets, are accessed from the Library (|lib|).

The library lists (and manages) all the aplets in the

calculator, whether they came with the calculator or were

added later. There are six types of math aplets built into the HP 38G :

Function

Parametric

Polar

• Real-valued, rectangular function y in terms of x. Example:

y = 2x-e3.

• Parametric functions x and y in terms of t. Example: x =

cos(0 and y = sin(f).

• Polar function r in terms of an angle 8.

Example: r = 2cos(40 ).

Getting Started 1-11

Sequence ® Sequence function i/in terms of n, or in terms of previous

terms in the sequence, such asUn~i and Example:

i/i = 0, f/2 = l,and a = +

Solve ® Finding the roots of an equation.

Example: x + 1 = -x-2.

Statistics e Analysis of one-variable (x) or two-variable (x and y)

statistical data.

Views

An aplet is represented in different ways. These views

compose an aplet problem and its solution. Here are illustrations of three major and six supporting aplet views.

SYMB

Symbolic view. The defining

equation(s) (in most aplets). The equation contains a

symbolic expression.

FUNCTION SVMtDLIC

^F10f>SIH<X)

F3<:x)=

F4<X>= F5<X>= ¥

PLOT

INUM!

Plot view. The graph of the

function(s).

Numeric view. Sampled

values of the function(s).

1-12 Getting Started

K: 0 FICH

.0ЦЦBЗЭH

.SRSSSOS .H7RH353

BHoai

: <! i8h:ih

■ [SETUPSYMB]

Symbolic Setup (■ |symb|). Sets parameters for the

symbolic expression.

FUMCTIDN SVMeOUC SETUP

ANGLE MEASURE:

CHMSE ANGLE MEASURE

Radian

■ [SETUPPLOT]

■ [SETUP-

NUM]

■ [VIEWS] Plot-Table

I [NOTE]

I [SKETCH]

Plot Setup (■ I PLOT I). Sets parameters to plot a graph.

Numeric Setup (■ | numQ. Sets parameters for building a table of numeric values.

Split Screen view. Two views side by side.

Note view. Text to

supplement an aplet.

Sketch view. Pictures to supplement an aplet.

^^^FONCIiDN PLDT KRNG: IMÜJiii VRNG; -3. 1 KTICK! 1 TTICK: 1 RES: Faster

ENTER MINIMUM HDRIZDNTAL VALUE

^^PUHCTIUN NUMERIC SETUP NUMSTART: ISHPBMBIlga NUMSTEP: . 1

NUMivPE: fiutomatic

NUMSBUM: 4

■ 6.5

3.2

ENTER STARTING VALUE FUR TAiLE

Changing Views

BannaHQi

BrjfaiinM

Each view is a separate “environment." To change the view,

press another view key. To change to Home, press | home |. You do not explicitly “close” the current view, you just enter another one-like passing from one room into another in a house.

Getting Started 1-13

Canceling To cancel an operation within a view, press |on| (the Operations CANCEL key). Pressing CANCEL will cancel pending

operations, but will not change the view.

Exploring an Aplet View by View

Example Use the Function aplet to explore the real function

y = sin(l/x)

using the Symbolic, Plot, and Numeric views. All the

information you enter is automatically saved

1. Open the Function aplet. Press

|lib|. If necessary, press 0 to

highlight Function.

Then press {{START}} to display the Symbolic view.

2. Enter the expression. (If necessary, highlight a new line or press I DEL I to clear the highlighted expression.)

Press

3. There are three Setup views. They are the shifted keystrokes for |symb|,

1 0 {{X}} {eñterI

I PLOT I, and |num|. Check that

Radians are set for Symbolic Setup; Press ■ [SETUP-SYMB] and choose Radians, if necessary.

Plot the graph. Press | plot |. The coordinates show that when .»=0, Kjk) is undefined.

(If your plot does not look like this, try resetting the default plot settings; Press ■ [SETUP-PLOT]

■ [CLEAR].)

Function

Parametric Polar Sequence Solye w

FUNCTION SVM6DÜC

F200 =

v<'FKH)=siHa^K>

F3(X)= F4<X)= F5<H)= w

FUNCTION SYMBOLIC SETUP

ANGLE MEASURE:

CHOOSE ANGLE MEASURE

............................

K; 0 FKK

Radian

: UNDEFINED IBiann

1-14 Getting Started

5. Trace the plot. Move the crosshairs

along the plot by pressing 0] and

B-

............................

i ' ' ' ' ' '

....,..

6. Zoom in and zoom out. Press

{{MENU}} {{ZOOM}}, highlight

In 4X4, and press {{OK}}.

To restore the original scale, select

{{ZOOM}} Un-zoom.

7. Display the numbers. To display a

table of data, press |num|. You see the independent (X) and dependent

(FI) variables listed with sampled

values.

(If your table does not look like this,

try resetting the default numeric settings : Press ■ [SETUP-NUM]

■ [CLEAR}.)

8. Split the screen. Press ■ [VIEWS],

then select Plot-Table {{OK}} to display these two views simultaneously.

K:1.3 FKK

i; .sissBas

K FI

-.60H3B -.HH?S3

-.HOSES

-.g03I3

s. HOSES

I.60H3P5

-.SEBBH

.SEBB35 .HH?535

Press I PLOT I to view the full-screen plot again.

Getting Started 1-15

Automatic With this example you have defined a new aplet-an aplet Saving containing data for the solution of y = sin(l/x). The data are

automatically saved in the Function aplet. If you want to create

another aplet based on Function, then you can give this one a new name in the Library ({{SAVE}}).

To keep as much memory available for storage as possible, delete aplets you no longer need.

Annotating The Note view (■ [NOTE}) attaches a note to the current

with Notes aplet. See “Notes and Sketches" later in this chapter. Annotating The Sketch view (■ [SKETCH]) attaches a picture to the

with Sketches current aplet. See “Notes and Sketches” later in this chapter.

Calculating in You can do calculations in aplets wherever you can enter

Aplets numbers or expressions. Use the math keys on the keyboard

or use operations from the | math | menu list. Chapter 2 discusses math calculations.

Catalogs and Editors

The HP 38G has several catalogs and editors. They access features and stored values (numbers or text or other items) that are not part of aplets. A catalog lists items, which you can delete or transmit. An editor lets you create or modify items and numbers.

Catalogs/Editors

Cataloe/Editor Contents Library ((051) Aplets. List (■ [UST]) Lists. In Home, lists are enclosed in {]. Matrix

One- and two-dimensional arrays. In

(■ [MATRIX]) Home, arrays are enclosed in [ ].

Notepad (■ [NOTEPAD])

Program (■ [PROGRAM])

Notes (short text entries).

Programs created by a user.

1-16 Getting Started

Storing £uid Recalling Variables

Variables are storage locations for numbers or values. The

HP 38G has different categories of variables for different kinds of data. The names for the variables are predefined. For real numbers, there are 27 variable names available, A through Z and 0. (Other categories and their names are in chapter 2.)

A variable holds just one value, so if you store a new number in it, any previous number is lost.

To store a

number

To recall a number

You can store a number from Home’s edit line into a named variable with the {{STO^}} (store) menu key. ({{STO^}} appears on a menu-key label whenever it is possible to store a value.) For example.

75{{STO^)} [TZzIA

ENTER

When you press | enter), the number 75 is stored into the

variable named A. To store the last answer, you don’t need to re-type the

number:

{{STO>}} [aIzIB

enter

This stores 75 (the last result) in B.

In Home, to recall a value from a stored variable back to the edit line, just type the name of the variable and press | enter].

i A...Z IA [enter! 75

7 5^A4

Ans ►Bi

Getting Started 1-17

“Deleting”

Variables

A variable always has a value in it, even if that value is zero. When you store another value into a variable, it overwrites the previous value. So you cannot delete a variable’s value, but you can overwrite it.

The predefined variable names (such as A through Z) always exist; you cannot change or delete them.

Home and Aplet Variables

Most variables are Home variables, which means they are shared throughout the different contexts of the calculator. Some variables are aplet variables, which means they apply

only to the current aplet. Aplet variables are data sets,

expressions, and settings made within an aplet.

Notes and Sketches

The HP 38G has compact text and picture editors for entering

notes and sketches.

® The Notepad is an independent collection of notes.

* Each aplet includes a Note view and a Sketch view for

that aplet only.

Note View and Sketch View

You can attach text to an aplet in its Note view (■ [NOTE]),

or attach pictures to it in its Sketch view (■ [SKETCH]).

To write a note 1. In an aplet, press ■ [NOTE] for the Note view. In Note view

2. Use the note editing keys shown below.

3. Set Alpha lock (([A...Z}}) for quick entry of letters. For

lowercase Alpha lock, press ■ ((A...Z}}.

® To type a single letter of the opposite case, press

■ letter.

4. Your work is automatically saved. When done, turn off

Alpha lock (by pressing ([A...Zh]}) if you want to go to

Home. (Otherwise, the | home | key will still type A.)

1-18 Getting Started

Note Editing Keys

Key Meaning

{{SPACE}} Space key for text entry. {{APACE}} Displays previous page of the note. {{PAGET}} {{A...Z}}

■ {{A...Z}} Lower-case Alpha-lock. {{BKSP}}

(HD

1 enter!

H {CLEAR] Erases the entire note.

1 VAR|

1 MATH 1

■ [CHARS] Displays special characters. To type one,

Displays next page of the note. Alpha-lock for letter entry.

Backspaces cursor and deletes character. Deletes current character. Starts a new line.

Menu for entering variable names, and contents of variables.

Menu for entering math operations, program commands, and constant names.

highlight it and press {{ECHO}}. Pressing

{{OK}} copies the character and closes the

CHARS screen.

To import a You can import a note from the Notepad into an aplet's Note

note view, and vice-versa.

1. Open the destination note in the Notepad or in the Note view of an aplet.

2. Press I var|.

* If the source note is in the Notepad, press {{HOME}},

highlight Notepad in the left-hand list, then highlight the name of the source note in the right-hand list.

* If the source note is part of the current aplet, press

{{APLET}}, highlight Note in the left-hand list, then

press 0 and highlight NoteText in the right-hand list.

3. Press {{VALUE}} {{OK}} to recall the contents of the source

note into the destination note.

Getting Started 1-19

Sketch Keys

To draw a sketch

Key Meanine

fPEH

■ [CLEAR] 0

1. In an aplet, press I

2. Press {{DRAW}}.

Stores the specified portion of the current sketch to a graphics variable (G1 through GO).

Adds a new, blank page to the current sketch set.

Displays previous sketch in the sketch set. Animates if held down.

Displays next sketch in the sketch set. Animates if held down.

Opens the edit line to type a text label.

Displays the menu-key labels for drawing (below).

Deletes the current sketch. Erases the entire sketch set.

Turns off the menu-key labels. Press any menu key to restore them.

[SKETCH] for the Sketch view.

3. Use the arrow keys to move the crosshairs (graphics cursor). To draw lines, boxes, or circles, use the menu keys (described next).

4. When done drawing, press {{OK}}. Your work is

automatically saved. Press any other view key or | home | to

exit the Sketch view.

1-20 Getting Started

To draw a line 1. In Sketch view, press {{DRAW}} and move the cursor to

where you want to start the line

2. Press {{LINE}}. This turns on line-drawing.

3. Move the cursor in any direction to the end point for the line.

4. Press {{OK}} to finish the line.

To draw a box 1. In Sketch view, press {{DRAW}} and move the cursor to

where you want any corner of the box to be.

2. Press {{BOX}}. This turns on box-drawing.

3. Move the cursor to mark the opposite corner for the box.

You can adjust the size of the box by moving the cursor.

4. Press {{OK}} to finish the box.

To draw a 1. In Sketch view, press {{DRAW}} and move the cursor to circle where you want the center of the circle to be.

2. Press {{CIRCL}}. This turns on circle-drawing.

3. Move the cursor the distance of the radius.

4. Press {{OK}} to draw the circle.

Getting Started 1-21

DRAW Keys

Key

Meaning

{{DOT-f}},

{{DOT-}} move. {{LINE}}

Dot on, dot off. Turns pixels on/off as crosshairs

Draws a line from the cursor’s starting position to the point at which you press {{ok}}. You can draw a line at any angle by moving the cursor.

Draws a box from the cursor's starting position to the point at which you press {{OK}}.

Draws a circle. The cursor’s starting position is the center of the circle. The cursor’s ending position (when you press {{ok}}) defines the radius.

To label parts 1. Press {{TEXT}} and type the text in the edit line. To lock of a sketch the Alpha shift on, press {{A...Z}} (for uppercase) or

■ {{A...Z}} (for lowercase).

2. To make the label a smaller character size, turn off

{{BIG«}}. (Pressing {{BIG}} turns on {{BIGh}} and vice-

versa.) The smaller character size cannot display lowercase letters.

3. Press {{OK}}. Use the arrow keys to position the label where you want it.

4. Press {{OK}} again to affix the label.

5. Press {{DRAW}} to continue drawing, or press | home | to

exit Sketch view.

To create a set You can create a sequence of up to ten sketches. This allows of sketches for simple animation.

« After making a sketch, press {{NEWP}} to add a new, blank

page that will follow the current page. You can now make a new sketch. The new image becomes part of the current set of sketches.

® To view the next sketch in an existing set, press

{{PAGET}}. Hold {{PAGET}} down for animation.

® To remove the current page in the current sketch series,

press [on |.

1-22 Getting Started

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