HP 39gs User Manual

5 (2)

HP 39gs graphing calculator

user's guide

Edition3

Part Number F2223AA-90001

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, NON-INFRINGEMENT AND FITNESS FOR A PARTICULAR PURPOSE.

HEWLETT-PACKARD CO. SHALL NOT BE LIABLE FOR ANY ERRORS OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, PERFORMANCE, OR USE OF THIS MANUAL OR THE EXAMPLES CONTAINED HEREIN.

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

Hewlett-Packard Company

16399 West Bernardo Drive

MS 8-600

San Diego, CA 92127-1899

USA

Printing History

Edition 2	December 2003
Edition 3	June 2005

Preface

Manual conventions ..............................................................	P-1
Notice .................................................................................	P-2
1 Getting started
On/off, cancel operations......................................................	1-1
The display ..........................................................................	1-2
The keyboard .......................................................................	1-3
Menus .................................................................................	1-8
Input forms ...........................................................................	1-9
Mode settings .....................................................................	1-10
Setting a mode...............................................................	1-11
Aplets (E-lessons).................................................................	1-12
Aplet library ..................................................................	1-16
Aplet views....................................................................	1-16
Aplet view configuration..................................................	1-18
Mathematical calculations ....................................................	1-19
Using fractions....................................................................	1-25
Complex numbers ...............................................................	1-29
Catalogs and editors ...........................................................	1-30
2 Aplets and their views
Aplet views ..........................................................................	2-1
About the Symbolic view ...................................................	2-1
Defining an expression (Symbolic view) ..............................	2-1
Evaluating expressions ......................................................	2-3
About the Plot view...........................................................	2-5
Setting up the plot (Plot view setup).....................................	2-5
Exploring the graph ..........................................................	2-7
Other views for scaling and splitting the graph ..................	2-13
About the numeric view...................................................	2-16
Setting up the table (Numeric view setup) ..........................	2-16
Exploring the table of numbers .........................................	2-17
Building your own table of numbers..................................	2-19
“Build Your Own” menu keys...........................................	2-20
Example: plotting a circle ................................................	2-20

3	Function aplet
	About the Function aplet........................................................	3-1
	Getting started with the Function aplet ................................	3-1
	Function aplet interactive analysis...........................................	3-9
	Plotting a piecewise-defined function ................................	3-12
4	Parametric aplet
	About the Parametric aplet ....................................................	4-1
	Getting started with the Parametric aplet.............................	4-1
5	Polar aplet
	Getting started with the Polar aplet .........................................	5-1
6	Sequence aplet
	About the Sequence aplet......................................................	6-1
	Getting started with the Sequence aplet ..............................	6-1
7	Solve aplet
	About the Solve aplet............................................................	7-1
	Getting started with the Solve aplet ....................................	7-2
	Use an initial guess...............................................................	7-5
	Interpreting results ................................................................	7-6
	Plotting to find guesses ..........................................................	7-7
	Using variables in equations ................................................	7-10
8	Linear Solver aplet
	About the Linear Solver aplet .................................................	8-1
	Getting started with the Linear Solver aplet..........................	8-1
9	Triangle Solve aplet
	About the Triangle Solver aplet ..............................................	9-1
	Getting started with the Triangle Solver aplet.......................	9-1
10 Statistics aplet
	About the Statistics aplet......................................................	10-1
	Getting started with the Statistics aplet..............................	10-1
	Entering and editing statistical data ......................................	10-6
	Defining a regression model..........................................	10-12
	Computed statistics ...........................................................	10-14
	Plotting............................................................................	10-15
	Plot types ....................................................................	10-16
	Fitting a curve to 2VAR data .........................................	10-17
	Setting up the plot (Plot setup view) ................................	10-18
	Trouble-shooting a plot .................................................	10-19

Exploring the graph ......................................................	10-19
Calculating predicted values..........................................	10-20
11 Inference aplet
About the Inference aplet .....................................................	11-1
Getting started with the Inference aplet .............................	11-1
Importing sample statistics from the Statistics aplet ..............	11-4
Hypothesis tests ..................................................................	11-8
One-Sample Z-Test..........................................................	11-8
Two-Sample Z-Test ..........................................................	11-9
One-Proportion Z-Test....................................................	11-10
Two-Proportion Z-Test ....................................................	11-11
One-Sample T-Test ........................................................	11-12
Two-Sample T-Test ........................................................	11-14
Confidence intervals..........................................................	11-15
One-Sample Z-Interval...................................................	11-15
Two-Sample Z-Interval ...................................................	11-16
One-Proportion Z-Interval...............................................	11-17
Two-Proportion Z-Interval ...............................................	11-17
One-Sample T-Interval ...................................................	11-18
Two-Sample T-Interval....................................................	11-19
12 Using the Finance Solver
Background........................................................................	12-1
Performing TVM calculations ................................................	12-4
Calculating Amortizations................................................	12-7
13 Using mathematical functions
Math functions ....................................................................	13-1
The MATH menu ............................................................	13-1
Math functions by category ..................................................	13-2
Keyboard functions.........................................................	13-3
Calculus functions...........................................................	13-6
Complex number functions...............................................	13-7
Constants ......................................................................	13-8
Conversions...................................................................	13-8
Hyperbolic trigonometry..................................................	13-9
List functions ................................................................	13-10
Loop functions..............................................................	13-10
Matrix functions ...........................................................	13-11
Polynomial functions .....................................................	13-11
Probability functions......................................................	13-12
Real-number functions ...................................................	13-13

iii

Two-variable statistics ...................................................	13-17
Symbolic functions .......................................................	13-17
Test functions...............................................................	13-18
Trigonometry functions..................................................	13-19
Symbolic calculations........................................................	13-20
Finding derivatives.......................................................	13-21
Program constants and physical constants ...........................	13-24
Program constants........................................................	13-24
Physical constants ........................................................	13-25
14 Variables and memory management
Introduction .......................................................................	14-1
Storing and recalling variables.............................................	14-2
The VARS menu..................................................................	14-4
Memory Manager ..............................................................	14-9
15 Matrices
Introduction .......................................................................	15-1
Creating and storing matrices ..............................................	15-2
Working with matrices ........................................................	15-4
Matrix arithmetic ................................................................	15-6
Solving systems of linear equations ..................................	15-8
Matrix functions and commands .........................................	15-10
Argument conventions ..................................................	15-10
Matrix functions ...........................................................	15-10
Examples.........................................................................	15-13
16 Lists
Displaying and editing lists ..................................................	16-4
Deleting lists..................................................................	16-6
Transmitting lists.............................................................	16-6
List functions.......................................................................	16-6
Finding statistical values for list elements................................	16-9
17 Notes and sketches
Introduction .......................................................................	17-1
Aplet note view ..................................................................	17-1
Aplet sketch view................................................................	17-3
The notepad ......................................................................	17-6
18 Programming
Introduction .......................................................................	18-1
Program catalog ............................................................	18-2
Creating and editing programs ............................................	18-4

Using programs ..................................................................	18-7
Customizing an aplet...........................................................	18-9
Aplet naming convention...............................................	18-10
Example......................................................................	18-10
Programming commands....................................................	18-13
Aplet commands ..........................................................	18-14
Branch commands ........................................................	18-17
Drawing commands......................................................	18-19
Graphic commands ......................................................	18-21
Loop commands ...........................................................	18-23
Matrix commands.........................................................	18-24
Print commands............................................................	18-26
Prompt commands ........................................................	18-26
Stat-One and Stat-Two commands ..................................	18-30
Stat-Two commands ......................................................	18-30
Storing and retrieving variables in programs....................	18-31
Plot-view variables ........................................................	18-32
Symbolic-view variables ................................................	18-39
Numeric-view variables .................................................	18-41
Note variables .............................................................	18-44
Sketch variables ...........................................................	18-44
19 Extending aplets
Creating new aplets based on existing aplets .........................	19-1
Using a customized aplet ................................................	19-3
Resetting an aplet................................................................	19-3
Annotating an aplet with notes .............................................	19-4
Annotating an aplet with sketches .........................................	19-4
Downloading e-lessons from the web.....................................	19-4
Sending and receiving aplets ...............................................	19-4
Sorting items in the aplet library menu list ..............................	19-6
Reference information
Glossary ..............................................................................	R-1
Resetting the HP 39gs............................................................	R-3
To erase all memory and reset defaults................................	R-3
If the calculator does not turn on.........................................	R-4
Operating details..................................................................	R-4
Batteries ..........................................................................	R-4
Variables .............................................................................	R-6
Home variables................................................................	R-6
Function aplet variables.....................................................	R-7
Parametric aplet variables .................................................	R-8

Polar aplet variables ........................................................	R-9
Sequence aplet variables ................................................	R-10
Solve aplet variables ......................................................	R-11
Statistics aplet variables..................................................	R-12
MATH menu categories.......................................................	R-13
Math functions...............................................................	R-13
Program constants..........................................................	R-15
Physical Constants .........................................................	R-16
Program commands .......................................................	R-17
Status messages .................................................................	R-18
Limited Warranty
Service ..........................................................................	W-3
Regulatory information.....................................................	W-5

Index

Preface

The HP 39gs is a feature-rich graphing calculator. It is also a powerful mathematics learning tool. The HP 39gs is designed so that you can use it to explore mathematical functions and their properties.

You can get more information on the HP 39gs from Hewlett-Packard’s Calculators web site. You can download customized aplets from the web site and load them onto your calculator. Customized aplets are special applications developed to perform certain functions, and to demonstrate mathematical concepts.

Hewlett Packard’s Calculators web site can be found at:

http://www.hp.com/calculators

Manual conventions

The following conventions are used in this manual to represent the keys that you press and the menu options that you choose to perform the described operations.

•Key presses are represented as follows:

, , , etc.

•Shift keys, that is the key functions that you access by

pressing the key first, are represented as follows:

CLEAR, MODES, ACOS, etc.

•Numbers and letters are represented normally, as follows:

5, 7, A, B, etc.

•Menu options, that is, the functions that you select using the menu keys at the top of the keypad are represented as follows:

, , .

•Input form fields and choose list items are represented as follows:

Function, Polar, Parametric

•Your entries as they appear on the command line or within input forms are represented as follows:

2*X2-3X+5

P-1

Notice

This manual and any examples contained herein are provided as-is and are subject to change without notice. Except to the extent prohibited by law, Hewlett-Packard Company makes no express or implied warranty of any kind with regard to this manual and specifically disclaims the implied warranties and conditions of merchantability and fitness for a particular purpose and Hewlett-Packard Company shall not be liable for any errors or for incidental or consequential damage in connection with the furnishing, performance or use of this manual and the examples herein.

♥ 1994–1995, 1999–2000, 2003–2006 Hewlett-

Packard Development Company, L.P.

The programs that control your HP 39gs are copyrighted and all rights are reserved. Reproduction, adaptation, or translation of those programs without prior written permission from Hewlett-Packard Company is also prohibited.

P-2

Getting started

On/off, cancel operations

To turn on	Press	to turn on the calculator.
To cancel	When the calculator is on, the			key cancels the
	current operation.
To turn off	Press	OFF to turn the calculator off.
	To save power, the calculator turns itself off after several
	minutes of inactivity. All stored and displayed information
	is saved.
	If you see the ((•)) annunciator or the Low Bat message,
	then the calculator needs fresh batteries.
HOME	HOME is the calculator’s home view and is common to all
	aplets. If you want to perform calculations, or you want to
	quit the current activity (such as an aplet, a program, or
	an editor), press		. All mathematical functions are
	available in the HOME. The name of the current aplet is
	displayed in the title of the home view.
Protective cover	The calculator is provided with a slide cover to protect the
	display and keyboard. Remove the cover by grasping
	both sides of it and pulling down.

You can reverse the slide cover and slide it onto the back of the calculator. this will help prevent you losing the cover while you are using the calculator.

To prolong the life of the calculator, always place the cover over the display and keyboard when you are not using the calculator.

Getting started

1-1

The display

To adjust the	Simultaneously press	and	(or	) to increase (or
contrast	decrease) the contrast.
To clear the display	• Press CANCEL to clear the edit line.

•Press CLEAR to clear the edit line and the display history.

Parts of the display

History	Title
	Title



Edit line		Menu key
Edit line

		labels
		labels

Menu key or soft key labels. The labels for the menu keys’ current meanings. is the label for the first menu key in this picture. “Press ” means to press the first menu key, that is, the leftmost top-row key on the calculator keyboard.

Edit line. The line of current entry.

History. The HOME display ( ) 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.

Title. The name of the current aplet is displayed at the top of the HOME view. RAD, GRD, DEG specify whether Radians, Grads or Degrees angle mode is set for HOME. The and symbols indicate whether there is more history in the HOME display. Press the and to scroll in the HOME display.

N O T E This user’s guide contains images from the HP 39gs and does not display the menu key label.

1-2	Getting started

Annunciators. Annunciators are symbols that appear above the title bar and give you important status information.

Annunciator Description

Shift in effect for next keystroke.

To cancel, press again.

αAlpha in effect for next keystroke. To cancel, press again.

((•))	Low battery power.
	Busy.
	Data is being transferred via
	infrared or cable.

The keyboard

Menu keys

HP 39gs

Graphing Calculator

Menu Key

Labels

Menu Keys

Aplet Control

Keys

Alpha Key

Shift Key

Cursor

Keys

Enter

Key

Getting started

1-3

•On the calculator keyboard, the top row of keys are called menu keys. Their meanings depend on the context—that’s why their tops are blank. The menu keys are sometimes called “soft keys”.

•The bottom line of the display shows the labels for the menu keys’ current meanings.

Aplet control keys

The aplet control keys are:

Key	Meaning

	Displays the Symbolic view for the
	current aplet. See “Symbolic view”
	on page 1-16.
	Displays the Plot view for the current
	aplet. See “Plot view” on page 1-16.
	Displays the Numeric view for the
	current aplet. See “Numeric view” on
	page 1-17.
	Displays the HOME view. See
	“HOME” on page 1-1.
	Displays the Aplet Library menu. See
	“Aplet library” on page 1-16.
	Displays the VIEWS menu. See
	“Aplet views” on page 1-16.

1-4	Getting started

Entry/Edit keys

The entry and edit keys are:

Key			Meaning

	(CANCEL)		Cancels the current operation if the
			calculator is on by pressing			.
			Pressing	, then OFF turns the
			calculator off.
			Accesses the function printed in blue
			above a key.
			Returns to the HOME view, for
			performing calculations.
			Accesses the alphabetical
			characters printed in orange below
			a key. Hold down to enter a string
			of characters.
			Enters an input or executes an
			operation. In calculations,
			acts like “=”. When		or
			is present as a menu key,
			acts the same as pressing			or
			.
			Enters a negative number. To enter
			–25, press	25. Note: this is not
			the same operation that the subtract
			button performs (		).
			Enters the independent variable by
			inserting X, T, θ, or N into the edit
			line, depending on the current
			active aplet.
			Deletes the character under the
			cursor. Acts as a backspace key if
			the cursor is at the end of the line.
	CLEAR		Clears all data on the screen. On a
			settings screen, for example Plot
			Setup,	CLEAR returns all
			settings to their default values.
,	,	,	Moves the cursor around the
			display. Press		first to move to
			the beginning, end, top or bottom.

Getting started

1-5

Key	Meaning	(Continued)

CHARS	Displays a menu of all available
	characters. To type one, use the
	arrow keys to highlight it, and press
	. To select multiple characters,
	select each and press		, then
	press	.

Shifted keystrokes

There are two shift keys that you use to access the operations and characters printed above the keys: and .

Key Description

Press the key to access the operations printed in blue above the keys. For instance, to access the Modes screen, press , then press . (MODES is labeled in blue above the key). You do not need to hold down when you press HOME. This action is depicted in this manual as “press

MODES.”

To cancel a shift, press again.

The alphabetic keys are also shifted keystrokes. For instance, to type Z, press Z. (The letters are printed in orange to the lower right of each key.)

To cancel Alpha, press again.

For a lower case letter, press

For a string of letters, hold down while typing.

1-6	Getting started

HELPWITH	The HP 39gs built-in help is available in HOME only. It
	provides syntax help for built-in math functions.
	Access the HELPWITH command by pressing
	SYNTAX and then the math key for which you require
	syntax help.
Example	Press	SYNTAX

Note: Remove the left parenthesis from built-in functions such as sine, cosine, and tangent before invoking the HELPWITH command.

Math keys

HOME (

) is the place to do calculations.

Keyboard keys. The most common operations are available from the keyboard, such as the arithmetic (like ) and trigonometric (like ) functions. Press to complete the operation: 256 displays 16.

MATH menu. Press

to open the MATH menu. The MATH menu is a comprehensive list of math functions that do not appear on the keyboard. It also

includes categories for all other functions and constants. The functions are grouped by category, ranging in alphabetical order from Calculus to Trigonometry.

•The arrow keys scroll through the list (, ) and move from the category list in the left column to the item list in the right column ( , ).

•Press to insert the selected command onto the edit line.

•Press to dismiss the MATH menu without selecting a command.

•Pressing displays the list of Program Constants. You can use these in programs that you develop.

Getting started

1-7

•	Pressing	displays a menu of physical
	constants from the fields of chemistry, physics,
	and quantum mechanics. You can use these
	constants in calculations. (See “Physical
	constants” on page 13-25 for more information.)
•	Pressing	takes you to the beginning of the

	MATH menu.
	See “Math functions by category” on page 13-2 for
	details of the math functions.
H I N T
	When using the MATH menu, or any menu on the
	hp 39gs, pressing an alpha key takes you straight to the
	first menu option beginning with that alpha character.
	With this method, you do not need to press		first.
	Just press the key that corresponds to the command’s
	beginning alpha character.
Program
	Pressing	CMDS displays the list of Program
commands	Commands. See “Programming commands” on
	page 18-13.
Inactive keys	If you press a key that does not operate in the current
	context, a warning symbol like this ! appears. There is
	no beep.

Menus

A menu offers you a choice of items. Menus are displayed in one or two columns.

•The arrow in the display means more items below.

•The arrow in the

display means more items above.

To search a menu

• Press

to scroll through the list. If you press

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 (or ).

1-8	Getting started

To cancel a menu

Input forms

Reset input form values

•If there are two columns, the left column shows general categories and the right column shows specific contents within a category. Highlight a general category in the left column, then highlight an item in the right column. The list in the right column changes when a different category is highlighted.

Press or when you have highlighted your selection.

•To speed-search a list, type the first letter of the word.

For example, to find the Matrix category in , press , the Alpha “M” key.

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

Press (for CANCEL) or . This cancels the current operation.

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 ( ). Some input forms include items to check ( ). See below for examples input forms.

To reset a field to its default values in an input form, move the cursor to that field and press . To reset all default field values in the input form, press CLEAR.

Getting started

1-9

Mode settings

You use the Modes input form to set the modes for HOME.

H I N T Although the numeric setting in Modes affects only HOME, the angle setting controls HOME and the current aplet. The angle setting selected in Modes is the angle setting used in both HOME and current aplet. To further configure an aplet, you use the SETUP keys ( and ).

Press	MODES to access the HOME MODES input
form.

Setting		Options

Angle		Angle values are:
Measure		Degrees. 360 degrees in a circle.
		Radians. 2π radians in a circle.
		Grads. 400 grads in a circle.
		The angle mode you set is the angle
		setting used in both HOME and the
		current aplet. This is done to ensure
		that trigonometric calculations done in
		the current aplet and HOME give the
		same result.
Number		The number format mode you set is the
Format		number format used in both HOME
		and the current aplet.
		Standard. Full-precision display.
		Fixed. Displays results rounded to a
		number of decimal places. Example:
		123.456789 becomes 123.46 in
		Fixed 2 format.
		Scientific. Displays results 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.

1-10	Getting started

Setting

Options (Continued)

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. Examples: 123.456789 becomes 123 in Fraction 2 format, and .333 becomes 1/3 and 0.142857 becomes 1/7. See “Using fractions” on page 1-25.

Mixed Fraction. Displays results as mixed fractions based on the specified number of decimal places. A mixed fraction has an integer part and a fractional part. Examples: 123.456789 becomes 123+16/35 in Fraction 2 format, and 7÷ 3 returns 2+1/3. See “Using fractions” on page 1-25.

Decimal Dot or Comma. Displays a number Mark 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 (dot) as separators in these contexts.

Setting a mode

This example demonstrates how to change the angle measure from the default mode, radians, to degrees for the current aplet. The procedure is the same for changing number format and decimal mark modes.

1.Press MODES to open the HOME MODES input form.

Getting started

1-11

The cursor (highlight) is in the first field, Angle Measure.

2.Press to display a list of choices.

3.Press to select Degrees, and press

. The angle measure changes to degrees.

4.Press to return to HOME.

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

Aplets (E-lessons)

Aplets are the application environments where you explore different classes of mathematical operations. You select the aplet that you want to work with.

Aplets come from a variety of sources:

•Built-in the HP 39gs (initial purchase).

•Aplets created by saving existing aplets, which have been modified, with specific configurations. See “Creating new aplets based on existing aplets” on page 19-1.

•Downloaded from HP’s Calculators web site.

•Copied from another calculator.

Aplets are stored in the Aplet library. See “Aplet library” on page 1-16 for further information.

You can modify

configuration settings for the graphical, tabular, and

1-12	Getting started

symbolic views of the aplets in the following table. See “Aplet view configuration” on page 1-18 for further information.

Aplet	Use this aplet to explore:
name

Function	Real-valued, rectangular functions y in
	terms of x. Example: y = 2x2 + 3x + 5 .
Inference	Confidence intervals and Hypothesis
	tests based on the Normal and
	Students-t distributions.
Parametric	Parametric relations x and y in terms of
	t. Example: x = cos(t) and y = sin(t).
Polar	Polar functions r in terms of an angle θ.
	Example: r = 2 cos(4θ) .
Sequence	Sequence functions U in terms of n, or
	in terms of previous terms in the same or
	another sequence, such as Un – 1 and
	Un – 2 . Example: U1 = 0 , U2 = 1
	and Un = Un – 2 + Un – 1 .
Solve	Equations in one or more real-valued
	variables. Example: x + 1 = x2 – x – 2 .
Finance	Time Value of Money (TVM)
	calculations.
Linear	Solutions to sets of two or three linear
Solver	equations.
Triangle	Unknown values for the lengths and
Solver	angles of triangles.
Statistics	One-variable (x) or two-variable (x and
	y) statistical data.

In addition to these aplets, which can be used in a variety of applications, the HP 39gs is supplied with two teaching aplets: Quad Explorer and Trig Explorer. You cannot modify configuration settings for these aplets.

A great many more teaching aplets can be found at HP’s web site and other web sites created by educators, together with accompanying documentation, often with student work sheets. These can be downloaded free of

Getting started

1-13

Quad Explorer aplet

charge and transferred to the HP 39gs using the provided Connectivity Kit.

The Quad Explorer aplet is used to investigate the behaviour of y = a(x + h)2 + v as the values of a, h and v change, both by manipulating the equation and seeing the change in the graph, and by manipulating the graph and seeing the change in the equation.

H I N T More detailed documentation, and an accompanying student work sheet can be found at HP’s web site.

Press	, select Quad
Explorer, and then press
. The Quad Explorer
aplet opens in
mode, in which the arrow
keys, the	and	keys,
and the	key are used to change the shape of the

graph. This changing shape is reflected in the equation displayed at the top right corner of the screen, while the original graph is retained for comparison. In this mode the graph controls the equation.

It is also possible to have the equation control the graph. Pressing displays a sub-expression of your equation.

Pressing the and key moves between subexpressions, while pressing the and key changes their values.

Pressing allows the user to select whether all three sub-expressions will be explored at once or only one at a time.

A button is provided to evaluate the student’s knowledge. Pressing displays a target quadratic graph. The student must

manipulate the equation’s parameters to make the equation match the target graph. When a student feels that they have correctly chosen the parameters a button evaluates the answer and provide feedback. An

button is provided for those who give up!

1-14	Getting started

Trig Explorer aplet The Trig Explorer aplet is used to investigate the behaviour of the graph of y = a sin(bx + c) + d as the values of a, b, c and d change, both by manipulating the equation and seeing the change in the graph, or by manipulating the graph and seeing the change in the equation.

Press , select Trig Explorer, and then press to display the screen shown right.

In this mode, the graph controls the equation. Pressing the and keys transforms the graph, with these

transformations reflected in the equation.

The button labelled		is	Origin
a toggle between			Origin
a toggle between
and	. When
is chosen, the ‘point of
control’ is at the origin (0,0)
and the	and
keys control vertical and
horizontal transformations. When				is chosen the

‘point of control’ is on the first extremum of the graph (i.e. for the sine graph at (π ⁄ 2,1) .

The arrow keys change the amplitude and frequency of the graph. This is most easily seen by experimenting.

Pressing displays the equation at the top of the screen. The equation is controlled by the graph. Pressing the and keys moves from parameter to parameter. Pressing the parameter’s values.

Extremum

or key changes the

The default angle setting for this aplet is radians. The angle setting can be changed to degrees by pressing .

Getting started

1-15

Aplet library

Aplets are stored in the Aplet library.

To open an aplet Press to display the Aplet library menu. Select the aplet and press or .

From within an aplet, you can return to HOME any time by pressing .

Aplet views

Symbolic view

Plot view

When you have configured an aplet to define the relation or data that you want to explore, you can display it in different views. Here are illustrations of the three major aplet views (Symbolic, Plot, and Numeric), the six supporting aplet views (from the VIEWS menu), and the two user-defined views (Note and Sketch).

Note: some aplets—such as the Linear Solver aplet and the Triangle Solver aplet—only have a single view, the Numeric view.

Press to display the aplet’s Symbolic view.

You use this view to define the function(s) or equation(s) that you want to explore.

See “About the Symbolic view” on page 2-1 for further information.

Press to display the aplet’s Plot view.

In this view, the functions that you have defined are displayed graphically.

See “About the Plot view” on page 2-5 for further information.

1-16	Getting started

Numeric view

Plot-Table view

Plot-Detail view

Overlay Plot view

Press to display the aplet’s Numeric view.

In this view, the functions that you have defined are displayed in tabular format.

See “About the numeric view” on page 2-16 for further information.

The VIEWS menu contains the Plot-Table view.

Select Plot-Table

Splits the screen into the plot and the data table. See “Other views for scaling and splitting the graph” on

page 2-13 for futher information.

The VIEWS menu contains the Plot-Detail view.

Select Plot-Detail

Splits the screen into the plot and a close-up.

See “Other views for scaling and splitting the graph” on page 2-13 for further information.

The VIEWS menu contains the Overlay Plot view.

Select Overlay Plot

Plots the current expression(s) without erasing any pre-existing plot(s).

See “Other views for scaling and splitting the graph” on page 2-13 for further information.

Getting started

1-17

Note view

Sketch view

Press NOTE to display the aplet’s note view.

This note is transferred with the aplet if it is sent to another calculator or to a PC. A note view contains text to supplement an aplet.

See “Notes and sketches” on page 17-1 for further information.

Press SKETCH to display the aplet’s sketch view.

Displays pictures to supplement an aplet.

See “Notes and sketches” on page 17-1 for further information.

Aplet view configuration

Plot Setup

Numeric Setup

Symbolic Setup

You use the SETUP keys ( , and ) to configure the aplet. For example, press

SETUP-PLOT ( ) to display the input form for setting the aplet’s plot settings. Angle measure is controlled using the MODES view.

Press SETUP-PLOT. Sets parameters to plot a graph.

Press SETUP-NUM. Sets parameters for building a table of numeric values.

This view is only available in the Statistics aplet in mode, where it plays an important role in choosing data models.

Press SETUP-SYMB.

1-18	Getting started

To change views Each view is a separate environment. To change a view, select a different view by pressing , , keys or select a view from the VIEWS menu. To change to HOME, press . You do not explicitly close the current view, you just enter another one—like passing from one room into another in a house. Data that you enter is automatically saved as you enter it.

To save aplet configuration

You can save an aplet configuration that you have used, and transfer the aplet to other HP 39gs calculators. See “Creating new aplets based on existing aplets” on page 19-1.

Mathematical calculations

Where to start

The most commonly used math operations are available from the keyboard. Access to the rest of the math functions is via the MATH menu ().

To access programming commands, press CMDS. See “Programming commands” on page 18-13 for further information.

The home base for the calculator is the HOME view

( ). You can do all calculations here, and you can access all operations.

Entering expressions

•Enter an expression into the HP 39gs in the same left- to-right order that you would write the expression. This is called algebraic entry.

•To enter functions, select the key or MATH menu item for that function. You can also enter a function by using the Alpha keys to spell out its name.

•Press to evaluate the expression you have in the edit line (where the blinking cursor is). An expression can contain numbers, functions, and variables.

Getting started

1-19

Example

Long results

Negative numbers

Scientific notation (powers of 10)

Example

Calculate	232	– 14	8	ln(45) :
Calculate	---------------------------	–3		ln(45) :
		–3

3 45

If the result is too long to fit on the display line, or if you want to see an expression in textbook format, press to highlight it and then press .

Type to start a negative number or to insert a negative sign.

To raise a negative number to a power, enclose it in parentheses. For example, (–5)2 = 25, whereas –52 = –25.

A number like 5 × 104 or 3.21 × 10–7 is written in scientific notation, that is, in terms of powers of ten. This is simpler to work with than 50000 or 0.000000321. To enter numbers like these, use EEX. (This is easier than using 10 .)