# 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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