2sin30°.cos²30°+sin30°.(1-2sin²30°)

Bab Trigonometri
Matematika SMA Kelas X

2 . sin 30° . cos² 30° + sin 30° . (1 - 2 sin² 30°)
= 2 . 1/2 . (1/2 √3)² + (1/2 . (1 - 2 . (1/2)²)
= 1 . (3/4) + (1/2 . (1 - 2 . 1/4))
= 3/4 + (1/2 . (4/4 - 2/4))
= 3/4 + (1/2 . 2/4)
= 3/4 + 1/4
= 4/4
= 1