Trigonometry For Dummies, 2nd Edition

Chapter 19

Graphing Sine and Cosine

In This Chapter

Looking at the basic graphs of sine and cosine

Working with variations of the graphs

Using sine and cosine curves to make predictions

The graphs of the sine and cosine functions are very similar. If you look at them without a coordinate axis for reference, you can't tell them apart. They keep repeating the same values over and over — and the values, or outputs, are the same for the two functions. These two graphs are the most recognizable and useful for modeling real-life situations. The sine and cosine curves can represent anything tied to seasons — the weather, shopping, hunting, and daylight. The equations and graphs of the curves are helpful in describing what happens during those seasons. You also find the curves used in predator-prey scenarios and physical cycles.

The ABCs of Graphing

You can graph trig functions in a snap — well, maybe not that fast — but you can do it quickly and efficiently with just a few pointers. If you set up the axes properly and have a general knowledge of the different functions’ shapes, then you're in business.

Different kinds of values represent the two axes in trig graphs. The x-axis is in angle ...