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# Proof of the cosine angle addition identity

Sal proves the identity cos(x+y) = cos(x)*cos(y) - sin(x)*sin(y). Created by Sal Khan.

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# Proof of the cosine angle addition identity

Current time: 0:00Total duration: 6:02

0 energy points

Sal proves the identity cos(x+y) = cos(x)*cos(y) - sin(x)*sin(y). Created by Sal Khan.