Beginning Math and Physics for Game Programmers

Degrees Versus Radians

Before we can delve into the world of trigonometry, it's imperative that we discuss angles and set standards for working with them. Obviously, angles are used for rotation, which we'll discuss in Chapters 6, “Transformations,” and 14, “Rotational Motion,”. They can also be used to establish a direction, which you'll see done in Chapter 4 and throughout the physics chapters. Let's identify the standards that will be used in those future chapters.

Every angle consists of two rays that intersect at a point called the vertex. We'll call one ray the initial side and the other ray the terminal side. To place an angle in standard position, we'll use the Cartesian coordinate system. The vertex should be at the origin (0,0), and ...