Trig identies part 3 (part 5 if you watch the proofs)

Learn more: http://www.khanacademy.org/video?v=JXCiFbEMTZ4
Continuation of the playing around with trig identities

Next in this playlist

Length: 9 minutes

Trigonometry word problems (part 1)

Length: 2 minutes

Trigonometry word problems (part 2)

Length: 9 minutes

Law of cosines