ABSTRACT
This chapter begins with an account of the real number system, together with its arithmetic laws and their consequences, because these represent the basis for the development of the theory of functions of one or more real variables. Experience suggests that in any systematic development of the properties of the real number system, the operations of addition and multiplication must play a fundamental role. The chapter explores the most frequently used trigonometric properties and identities. In mathematics, when working with trigonometric functions the argument of the function is always in radians and never in degrees. Knowledge of the elements of rectangular Cartesian coordinate geometry and of polar coordinates is essential for an understanding of the geometrical implications of many properties of functions, and also for applications of mathematics to physical problems. The chapter describes the elements of the real number system in a straightforward manner.
