ABSTRACT
This chapter begins by introducing the related concepts of a variable and a function that together form the basis of analysis. The definition of a function of a single real variable as a relationship in which one value of the independent variable corresponds to only one value of the dependent variable, and conversely, then leads, by interchanging the roles of the dependent and independent variables, to the important concept of an inverse function. The graphical interpretation of the inverse of a function as the reflection of the graph of the function in the line y = x simplifies its construction. Special care is taken with the discussion of the inverse trigonometric functions because their periodicity makes it necessary to introduce a principal branch for each trigonometric function.
