P-1
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*X
2
-3X+5
HP 39gs English.book  Page 1  Wednesday, December 7, 2005  11:24 PM