The Pythagorean Identity

As we have just learned about the trigonometric functions, there is actually a way to relate these, in this very unit circle.

The reason the unit circle exists is to enforce a relation called The Pythagorean Identity.
Or, the Fundamental Theorem of Trigonometry.

It relates the sine and cosine in the following equation:YOU MUST REMEMBER THIS.
EVERY. SINGLE. TRIGONOMETRIC IDENTITY CAN BE DERIVED FROM THIS BASIC RELATIONSHIP!

Before we can fully start diving into this topic, you first need to learn about The Radian