Hitunglah sin 285 derajat - sin 75 derajat adalah?

sin 285 - sin 75
= sin (270+15) - sin (90-15)
= -cos 15 - cos 15
= - 2. cos 15
= -2 cos (45-30)
= -2 {cos 45 cos 30 - sin 45 sin 30}
= -2{(√2/2)(√3/2) - (√2/2)(1/2)}
= -2{(√6/4) - (√2/2)}
= -(√6/2) + √2