Find the exact value of Cosine (StartFraction 5 pi Over 6 EndFraction) cosine (StartFraction pi over 12 EndFraction) + sine (StartFraction 5 pi Over 6 EndFraction) sine (StartFraction pi Over 12 EndFraction)

Find the exact value of Cosine StartFraction 5 pi Over 6 EndFraction cosine StartFraction pi over 12 EndFraction sine StartFraction 5 pi Over 6 EndFraction sine class=