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Khan Academy on a Stick
Examples using Pythagorean identities to simplify trigonometric expressions
Trigonometric identities
Trigonometry Identity Review/Fun
Trigonometric Identities
Examples using Pythagorean identities to simplify trigonometric expressions
Proof: sin(a+b) = (cos a)(sin b) + (sin a)(cos b)
Proof: cos(a+b) = (cos a)(cos b)-(sin a)(sin b)
Trig identities part 2 (part 4 if you watch the proofs)
Trig identies part 3 (part 5 if you watch the proofs)
Cosine addition identity example
Double angle formula for cosine example
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