tentukan nilai dari cos 15 - sin 15

cos 15°-sin 15°

cos (45-30)°-sin(45-30)°
cos 45.cos 30+ sin 45.sin 30 - (sin 45.cos 30-sin 30.cos 45)

(cos 45.cos 30) + (sin 45.sin 30)-(sin 45.cos 30)+(sin 30.cos 45)

ingat bahwa sin 45 = cos 45, jadi (cos 45.cos 30 )= (sin 45.cos 30) dan (sin 45.sin 30) = (sin 30.cos 45)

(cos 45.cos 30)-(sin 45.cos 30)+(sin 45.sin30)+(sin 30.cos 45)


2(sin 45.sin 30)
2.sin 45.1/2
jadi jawabannya = sin 45°
= 1/2 akar 2