The Objective of This Book

Numerical methods require extensive calculation, which is easily accomplished using today's desktop computers. A number of books have been written in which numerical methods are implemented using a specific programming language, such as FORTRAN or C++. Most scientists and engineers received some training in computer programming in their college days, but they (or their computer) may no longer have the capability to write or run programs in, for example, FORTRAN. This book shows how to implement numerical methods using Microsoft Excel@, the most widely used spreadsheet software package. Excel@ provides at least three ways for the scientist or engineer to apply numerical methods to problems:

• by implementing the methods on a worksheet, using worksheet formulas
• by using the built-in tools that are provided within Excel
• by writing programs, sometimes loosely referred to as macros, in Excel's Visual Basic for Applications (VBA) programming language.

All of these approaches are illustrated in this book.

This is a book about numerical methods. I have emphasized the methods and have kept the mathematical theory behind the methods to a minimum. In many cases, formulas are introduced with little or no description of the underlying theory. (I assume that the reader will be familiar with linear interpolation, simple calculus, regression, etc.) Other topics, such as cubic interpolation, methods for solving differential equations, and so on, are covered in more detail, and a few topics, such as Bairstow's method for obtaining the roots of a regular polynomial, are discussed in detail.

In this book I have provided a wide range of Excel solutions to problems. In many cases I provide a series of examples that progress from a very simple implementation of the problem (useful for understanding the logic and construction of the spreadsheet or VBA code) to a more sophisticated one that is more general. Some of the VBA macros are simple "starting points" and I encourage the reader to modify them; others are (or at least I intended them to be) "finished products" that I hope users can employ on a regular basis.

Nearly 100% of the material in this book applies equally to the PC or Macintosh versions of Excel. In a few cases I have pointed out the different keystrokes requires for the Macintosh version.