It's the sine! No, it's the tangent! No, it's the cosine! Alright, so maybe evaluating trigonometric functions isn't as exciting as spotting Superman in the sky. But we bet you jump for joy the first time you solve for cosine.

Up Next:
Verifying Trig Identities 
Up Next:
Tangent HalfAngle Formula 
Up Next:
Special Right Triangles 
Up Next:
SOHCAHTOA 
Up Next:
Sines 
Up Next:
Law of Sines 
Up Next:
Law of Cosines