HP 15c Collector's Edition User Manual

174 Section 12: Calculating with Matrices
Conditional Tests on Matrix Descriptors
Four conditional tests—~, T 0 (x ≠ 0), T 5 (x = y), and
T 6 (x ≠ y)—can be performed with matrix descriptors in the X- and
Y-registers. Conditional tests can be used to control program execution,
as described in Section 8.
If a matrix descriptor is in the X-register, the result of ~ will be false
and the result of T 0 will be true (regardless of the element values
in the matrix.)
If matrix descriptors are in the X- and Y-registers when T 5 or T
6 conditional test is performed, x and y are equal if the same descriptor
is in the X- and Y-registers, and not equal otherwise. The comparison is
made between the descriptors themselves, not between the elements of
the specified matrices.
Other conditional tests can’t be used with matrix descriptors.
Stack Operation for Matrix Calculations
During matrix calculations, the contents of the stack registers shift much
like they do during numeric calculations.
For some matrix calculations, the result is stored in the result matrix. The
arguments—one or two descriptors or numbers in the X-register or the
X- and Y-registers—are combined by the operation, and the descriptor of
the result matrix is placed in the X-register. (The argument from the X-
register is placed in the LAST X register.)

HP 15c Collector's Edition Specifications

General

Model	HP 15c Collector's Edition
Category	Calculator
Type	Scientific
Power Source	Battery
Manufacturer	HP
Display	LCD
Functions	complex numbers, matrix operations

Summary

Introduction

This Handbook

Outlines the structure of the manual, detailing its parts and how to use it for learning.

The HP Community

Discusses user groups and websites for HP calculator enthusiasts and information sharing.

Part I: HP 15c Fundamentals

Section 1: Getting Started

Covers basic operations like powering on, keyboard layout, and primary/alternate functions.

Section 2: Numeric Functions

Explains essential numeric operations including logs, trig, powers, and conversions.

Section 3: The Automatic Memory Stack, LAST X, and Data Storage

Details the RPN stack, LAST X register, and data storage operations.

Part II: HP 15c Programming

Section 6: Programming Basics

Introduces core programming concepts: creating, loading, running programs, and memory.

Section 8: Program Branching and Controls

Covers controlling program flow using branching, loops, and conditional tests.

Part III: HP 15c Advanced Functions

Section 11: Calculating With Complex Numbers

Covers entering, manipulating, and performing calculations with complex numbers.

Section 12: Calculating With Matrices

Explains matrix operations, including dimensioning, element access, and calculations.

Section 13: Finding the Roots of an Equation

Details using the SOLVE function for numerical root finding and equation solving.

Section 14: Numerical Integration

Explains how to perform numerical integration using the ∫f(x)dx key and subroutines.

Appendix A: Error Conditions

Error 8: No Root

Explains the error when the SOLVE function cannot find a root.

Error 0: Improper Mathematics Operation

Lists and explains errors related to mathematical operations and illegal arguments.

Appendix D: A Detailed Look at SOLVE

How SOLVE Works

Explains the numerical technique and logic behind the SOLVE algorithm.

Finding Several Roots

Discusses methods for finding multiple roots of an equation using the SOLVE function.