HP HP-28S User Manual

The functions MAXR (maximum real) and MINR (minimum real) return
symbolic constants for the largest and smallest positive real numbers
representable on the HP-28S. (To force a numerical result for a sym-
bolic constant, see HUsing 1['H on page 74.)
This section shows you how to use the function NEG. For conve-
nience, you can execute NEG by pressing [ CHS I (change sign) if no
command line is present. To enter the NEG command in the com-
mand line-for example, when you're keying in a program-press
NEG or [ill []] @].
Now negate the number in level 1 twice, once by pressing [ CHS I and
once by pressing NEG .
Negate the number in level 1.
ICHSI
3: -2. 06761537357E-13
2: 0
1: -2.46855006079
CIHImJIDlI:IIDaGIllmlGmm
Negate the number a second time.
NEG
3: -2. 06761537357E-13
2: 0
1: 2.46855006079
CIHImJIDlI:IIDaGIllmlGmm
Defining New Functions
You can create program variables that work like the built-in func-
tions-you can even use them in expressions. Such program variables,
called user functions, must fulfill two requirements:
• They must explicitly indicate their arguments .
• They must return exactly one result.
5: Real-Number Functions 79

HP HP-28S Specifications

General

Introduced	1988
Memory	32 KB
Number of Digits	12
Type	Scientific Calculator
Manufacturer	Hewlett-Packard (HP)
Display	LCD
Processor	Saturn
Programming	RPL

Summary

HP-28S Advanced Scientific Calculator Owner's Manual

Part 1: Fundamentals

Introduces basic operations, calculator features, and core concepts.

Getting Started

Covers initial setup, basic operations, and calculator overview.

Doing Arithmetic

Explains methods for performing calculations using stack and expressions.

Part 2: Summary of Calculator Features

Objects

Describes fundamental data types, symbolic operations, and programming elements.

The Command Line

Explains input methods, cursor control, and command entry.

The Stack

Reviews stack concepts and commands for manipulating objects.

Part 3: Programming

Program Structures

Covers conditional logic, loops, and error handling in programs.

Conditional Structures

Explains testing conditions and making decisions within programs.

Definite Loop Structures

Details structures for executing code a specific number of times.

Appendixes & Indexes

Appendix A: Assistance, Batteries, and Service

Provides troubleshooting, battery info, and service details.

Answers to Common Questions

Addresses frequent user queries and common calculator issues.

Appendix B: Notes for HP RPN Calculator Users

Highlights differences for users familiar with RPN calculators.

Appendix D: Menu Map

Lists commands by menu, with descriptions and page references.

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