tentukan nilai cos 45° - cos 15°

cos 45° - cos 15°=1/2-1/3=1/6

soal !
cos 45° - cos 15°
jawab :
cos 45° = 1/2 akar 2
cos 15° = cos(45° - 30°)
= 1/2 akar 2 - 1/2 akar 3
= 1/2(akar 2 - akar 3)

cos 45° - cos 15° = 1/2akar 2 - 1/2(akar 2 -akar 3)
= 1/2 akar 3