trig math 30

Find the exact value of cos 8 degrees cos 38 degrees + sin 8 degrees sin 38 degrees

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  1. Did you recognize the
    cos (A-B) = cosAcosB + sinAsinB pattern ?

    so cos8ºcos38º + sin8ºsin38º
    = cos (8-38)
    = cos (-30)
    = cos 30
    = √3/2

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