Introduction Introductory Algebra Logarithms to the Base 10 Natural Logarithms Essentials of Trigonometry B.2 INTRODUCTION B.2.1 Symbols and Notation A symbol is commonly used in algebra to represent a quantity. Symbols are also used to indicate a mathematical operations such as +, -, X, and . A symbol also may be used to designate an absolute constant. For instance, the speed of light is often annotated by the letter C. We frequently reach into the Greek alphabet; for example, IT is used to calculate the circumference or area of a circle given its diameter or radius. Let's say that notation is a specific symbol or specific symbols used in a particular procedure or equation. For example, a is nearly universally used for wavelength; F or f for frequency. Z is used for impedance and Z, for characteristic impedance. As we said, a symbol in algebra represents a specific quantity. X is the unknown, or X = the unknown (quantity). If there is a second unknown, we're apt to call it y. These rules are never hard and fast. For instance, if we are dealing with a geometrical figure with height, length, and width, we would probably use H for height, L for length, and W Fundamentals of Telecommunications, Second Edition, by Roger L. Freeman ISBN 0-471-71045-8 Copyright © 2005 by Roger L. Freeman A REVIEW OF MATHEMATICS FOR TELECOMMUNICATION APPLICATIONS for width; and we'd assign r for radius and d for diameter when dealing with something circular. Angles are often represented by the symbols a and B, and O is also widely used to represent an angle. These are just more examples of utilizing the Greek alphabet as well as the Roman. Subscripts. A subscript tells us something about a symbol. For example, PdBW would probably mean "the power expressed in dBW." We might discuss the velocities of two cars. The velocity of car 1 may be expressed as V1, and the velocity of car 2 is expressed as V2. The use of the subscript allows us to distinguish between the two cars. Subscripts are used widely in the text. Independent and Dependent Va