diketahui sin alpa cos beta = 2/5 dan ( alpa+beta) = 5 phi/6 . nilai sin(alpa-beta)=

Jawaban ada di lampiran

A + B = 5π/6 = 150° => sin (A + B) = sin 150° = 1/2

2 sin A cos B = sin (A + B) + sin (A - B)
2 (2/5) = 1/2 + sin (A - B)
4/5 - 1/2 = sin (A - B)
sin (A - B) = (8 - 5)/10 = 3/10