Cos 5Π/12=1/4(√6-√2)

Mapel : Matematika
Kelas : X SMA
Bab : Trigonometri

Pembahasan :
Cos (5.180/12) = 1/4(√6 - √2)
Cos 75° = 1/4(√6 - √2)
Cos (90 - 15)° = 1/4(√6 - √2)
Sin 15° = 1/4(√6 - √2)
Sin (45 - 30)° = 1/4(√6 - √2)
Sin 45° . Cos 30° - Cos 45 . Sin 30° = 1/4(√6 - √2)
(1/2 √2)(1/2 √3) - (1/2 √2)(1/2) = 1/4(√6 - √2)
1/4 √6 - 1/4 √2 = 1/4(√6 - √2)
1/4(√6 - √2) = 1/4(√6 - √2)

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