ôô

# The World of Trigonometry

You've probably heard of sine, cosine, and tangent before. But do you actually know what they are? While they sound like complicated ideas, they're really not. Keep on reading to learn more about the origins and uses of trigonometry.

By
Jason Marshall, PhD,
January 11, 2014
Episode #181

Page 1 of 2

Do you know what all of the buttons on your calculator do? If you're the kind of person who likes to rock one of those quaint old-timey super-simple calculators that only perform basic arithmetic, the answer is probably, "Yes." But if you're sporting one of those ever-popular modern gizmos like a graphing calculator, smartphone, or computer, there are probably more than a couple of buttons that you're completely befuddled by.

If that's you, good news: today we're going to kick off a discussion of trigonometry—a topic that sounds hard but is really pretty easy, and a subject that a bunch of those bewildering buttons can help you deal with. What are those magic buttons? And what do they do? Stay tuned because those are precisely the questions we'll be answering over the next few weeks..

## What Is Trigonometry?

Before we can talk about what those "sin," "cos," and "tan" buttons on your calculator are for, we first need to talk about trigonometry. Why? Because those buttons represent three of the most common functions that are used in trigonometry—so called "trigonometric functions": sine, cosine, and tangent.

So, what is all of this trigonometry stuff about?

Well, as you might be able to guess from the first part of the word, the part of math known as trigonometry deals with triangles. The word trigonometry actually comes from the Greek words trigon meaning—no big surprise here—triangle, and metron meaning something like “measure.” Which makes a lot of sense since trigonometry is all about figuring out clever ways to measure and calculate the properties of the components of triangles—namely their three sides and three angles.

The basic ideas underlying trigonometry have been around for a while…a very long while. In fact, trigonometry is one of the older branches of mathematics. Its ideas were first developed over 2,000 years ago by people who were figuring out the most efficient way to observe, measure, and make sense of the movements of astronomical bodies. So now you know who to blame for those extra buttons on your calculator (although, in truth, you really ought to be thanking them!).