Introduction to Trigonometry

By Matthew Stephens
266
2026

Description

This college level trigonometry text may be different than most other trigonometry textbooks. In this book, the reader is expected to do more than read the book but is expected to study the material in the book by working out examples rather than just reading about them. So the book is not just about mathematical content (although it does contain important topics in trigonometry needed for further study in mathematics), but it is also about the process of learning and doing mathematics and is designed not to be just casually read but rather to be engaged. Recognizing that actively studying a mathematics book is often not easy, several features of the textbook have been designed to help students become more engaged as they study the material. This book will provide a welcome resource for students seeking an undergraduate text on advanced trigonometry, when few are readily available. Ideal for selfstudy, this text offers a clear, logical presentation of topics and an extensive selection of problems with answers. The book covers all areas of trigonometry including the theory and equations of tangent, sine and cosine, using trigonometry in three dimensions and for angles for any magnitude, related to triangles. Everything you will need is here in this one book. Each chapter includes not only an explanation of the knowledge and skills you need, but also worked examples and test questions. This book represents a novel approach for the trigonometry and an original scientific work in this field, by using the ensemble structure composed of the real analysis and the axiomatic fundaments of geometry. Throughout this book one presents, in a proper manner, definitions, properties, formulae and applications more specific of the subject title and its immediate connections. The book is recommended as a pertinent introduction for the university students, mathematics teachers and anyone who is interested in the major elements regarding the essence of real mathematics.

About Author

Matthew Stephens is an Adjunct Faculty member of the Department of Mathematics at Schoolcraft College. He received a B.A. in Mathematics from the University of California at Berkeley, and received an M.A. in Mathematics and an M.S. in Industrial & Operations Engineering from the University of Michigan. Stephens conducted postdoctoral research with Peter Donnelly at the University of Oxford. Stephens was awarded the Guy Medal (bronze) in 2006. He was elected a Fellow of the Royal Society in 2023.

Table of Content

Preface
Chapter 1. Basics of Angles and Triangles

Concept and Types of Angles
Measuring Angles: Degrees and Radians
Types of Triangles and Properties 
Angle Sum Property of Triangles
Exterior and Interior Angles

Chapter 2. Introduction to Trigonometric Ratios
Right-Angled Triangle and Perpendicular-Base-Hypotenuse
Definition of Sine, Cosine, and Tangent
Definition of Cosecant, Secant, and Cotangent
Trigonometric Ratios Using Unit Circle
Reciprocal Identities

Chapter 3. Trigonometric Identities
Fundamental Identities
Product and Quotient Identities
Verification of Identities
Trigonometric Equations
Applications in Problem Solving

Chapter 4. Trigonometric Ratios of Compound Angles
Sum and Difference Formulas
Sine and Cosine of Multiple Angles
Tangent of Multiple Angles
Applications in Solving Equations

Chapter 5. Trigonometric Ratios of Multiple and Sub-Multiple Angles
Double Angle Formulas
Triple Angle Formulas
Half-Angle Formulas
Transformation of Product to Sum
Simplification Techniques
Chapter 6. Inverse Trigonometric Functions
Concept of Inverse Trigonometric Functions
Principal Values and Ranges
Properties and Identities
Applications in Integration and Geometry
Domain and Range Considerations

Chapter 7. Graphs of Trigonometric Functions
Trigonometric Functions
Amplitude, Period and Phase Shift
Graphs of Secant and Cosecant
Graph Transformations
Applications in Wave Analysis

Chapter 8. Trigonometric Equations
General Solutions of Trigonometric Equations
Equations Involving Multiple Angles
Equations Using Trigonometric Identities
Applications in Geometry and Physics
Use in Architecture and Engineering

Chapter 9. Heights and Distances
Angle of Elevation and Depression
Line of Sight Concept
Use of Trigonometric Ratios in Solving Problems
Simple Problems Involving Right Triangles
Multiple Object Height/Distance Problems

Chapter 10. Applications of Trigonometry
Trigonometry in Physics (Waves, Oscillations)
Navigation and Surveying
Astronomy and Geography
Architecture and Engineering Applications
Use in Signal and Sound Analysis

Bibliography