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Verifying Identities Trigonometric

Video title: Proof of cos(a+b) = (cos a)(cos b)-(sin a)(sin b)

An online trigonometry video that teaches students about the Proof of the trigonometric identity: cos(a+b) = (cos a)(cos b)-(sin a)(sin b)

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Khan Academy videos are licensed under a Creative Commons 3.0 License. This video is owned and provided free of cost by Khan Academy. Copyright Khan Academy 2010

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