Hitunglah 2 sin 127,5° sin 97,5°

2 Sin 127,5° Sin 97,5°
= – Cos (127,5 + 97,5)° + Cos (127,5 – 97,5)°
= – Cos 225° + Cos 30°
= – (-1/2akar 2) + 1/2akar 3
= 1/2 akar 2 + 1/2 akar 3
= 0,70 + 0,86
= 1,56