Radians (a.k.a. "angles with Pi in them")

If you've already checked out my SohCahToa and Unit Circle pages prior to this, you may have noticed that to keep it simple I didn't use radians at all, everything was degrees. So if you're totally lost on the unit circle, I'd encourage you to go back and get solid using my degrees-only videos first. The main thing to keep in mind is that radians are just another unit of measure -- like miles vs kilometers. With practice -- and the tricks I show you in these videos -- you'll get to where you just recognize radian measures and can do them in your head.

Trig Functions of Radians

In this video we'll learn how to find the sine and cosine of all those nasty radian angles on the unit circle, and we'll practice finding the trig functions of them in a bunch of examples. We'll also learn the best trick ever for quickly converting radian angles to degrees -- in your head -- using just the denominator!

Tips For Memorizing Radian Unit Circle

In this video I get into all the stuff from the unit circle chapter, except this time with radians. Negative angles. Improper fractions. And of course, awesome tricks to help you do problems like sin(5pi/6) in your head. I'll show you how simple patterns can be used to write out the unit circle, anytime you need it.

How to Convert Radians to Degrees

Not only is this a useful skill if you're more comfortable with degrees than radians, it's also a type of problem that every trig teacher puts on quizzes and tests. In this video I show you how to convert radians to degrees, and degrees to radians, and as usual I work a bunch of examples.

How to find Co-Terminal Angles with Radians

If you're a fraction hater, this one isn't going to be too pretty, since we're going to be adding 2 pi to lots of crazy fractions. But hey, practice a little here, and you'll do fine on the test!