Pythagorean Identity. This identity is so named because we can read it off of the unit circle by looking at any of the right triangles and remembering the Pythagorean Theorem.
-
Proof of the pythagorean identity
(6:12)
-
Using the Pythagorean trig identity (6:15)
Given thatand that
is in the third quadrant, Sal finds
.
-
Solving problems of the type: given that
is in the third quadrant and that
, find
.