Sederhanakan 4 sin π/8 cos 7π/24

TriGonoMetRi

2 cos a sin b = sin (a + b) - sin (a - b)

•••
a = 7π/24
b = π/8

4 cos 7π/24 sin π/8
= 2 . 2 cos 7π/24 sin 3π/24
= 2 (sin (7π/24 + 3π/24) - sin (7π/24 - 3π/24))
= 2 (sin 5π/12 - sin π/6)
= 2 (sin 150° - sin 30°)
= 2 . 0
= 0