In this chapter, we will look at some special types of functions that are commonly used in calculus: trigonometric functions. Additionally, we will look at solving complicated equations for a given variable and finding all of the points where two functions intersect each other. Each of these skills are quite important in calculus. Trigonometric functions help model natural phenomena such as sound and light waves, and are used in related rates to determine how quickly something, like an angle, is changing. Because of the varied applications you will see in calculus, familiarity with these functions is a must. We will also look at a way that we can take a rational function and write it in a different form. Sometimes, one of these forms will be more useful to us than another form, particularly in integral calculus where we will have rules that only work for certain function forms. When we look at the intersections of two functions, we will mostly focus on polynomials in this chapter since they are commonly used functions in scientific fields. Intersections will be used frequently in integral calculus when we are determining the area enclosed by two or more functions.
Thumbnail: The trigonometric functions are functions of an angle. and relate the angles of a triangle to the lengths of its sides. They are important in the study of triangles and modeling periodic phenomena, among many other applications. (CC BY 4.0; OpenStax)