Trigonometry For Dummies, 2nd Edition

Chapter 7

Doing Right by Trig Functions

In This Chapter

Understanding the three basic trig functions

Building on the basics: The reciprocal functions

Recognizing the angles that give the cleanest trig results

Determining the exact values of functions

By taking the lengths of the sides of right triangles or the chords of circles and creating ratios with those numbers and variables, our ancestors marked the birth of trigonometric functions. These functions are of infinite value, because they allow you to use the stars to navigate and to build bridges that won't fall. If you're not into navigating a boat or engineering, then you can use the trig functions at home to plan that new addition. They're a staple for students going into calculus.

The six trig functions require one thing of you — inputting an angle measure — and then they output a number. These outputs can be any real numbers, from infinitely small to infinitely large and everything in between. The results you get depend on which function you use. Although some of the early-day computations were rather tedious, today's hand-held ...