This trigonometry workbook focuses on trig identities. The majority of the exercises let you derive a variety of trig identities by following similar examples. If you get stuck, helpful hints in the back of the book help walk you through the solution. Other exercises include applications, such as how to find the tangent of 15 degrees without a calculator or how to apply trig identities to solve equations. This book also serves as a handy list of numerous trig identities organized by topic. The answer to every problem can be found at the back of the book. The author, Chris McMullen , Ph.D., has over twenty years of experience teaching math skills to physics students. He prepared this workbook of the Improve Your Math Fluency series to share his knowledge of trig identities.