nilai 10 cos 20° cos 40° cos 80° adalah
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nilai 10 cos 20° cos 40° cos 80° adalah
1 Jawaban
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1. Jawaban asobri68
= 10 cos (20°)*cos(40°)*cos (80°)
= (10)*((cos (20° + 40°) + cos (20° - 40°))/2)*cos (80°)
= (10)*((cos (60°) + cos (-20°))/2) * cos (80°)
= (10 cos (80°))*((cos (60°) + cos (-20°))/2
= 5 cos (80°)*((cos (60°) + cos (-20°))
= 5 cos (80°)*((cos (60°) + cos (20°))
= 5 cos (80°)*(1/2 + cos (20°))
10 cos 20° cos 40° cos 80° =