## Video problem-solving examples

Examples and derivations from the wonderful world of trigonometry

## 1. Counting around the unit circle

You should know how to label the most-frequently-used angles around the unit circle (circle of radius r = 1), both in degrees and radians. It's not that difficult if you just think of it as counting around the circle in different increments.

## 2. The special triangles: 45-45-90 and 30-60-90

You'll make your journey through trigonometry much easier if you memorize everything needed to derive the trig functions of 30˚, 45˚ and 60˚ angles. Here's how to do it.

## 3. Using basic right-triangle trigonometry

Here are two examples of how we use SOH-CAH-TOA trig. to solve for the missing sides of a right triangle. This is a basic skill in trigonometry that you should master.

Minutes of your life: 4:48 (two examples)

## 4. Non-right triangles: Derivation of the law of sines

The law of sines is an important relationship between the angle measures and side lengths of non-right triangles. In this video you'll see where it comes from.