Question

Sin(60 - A) Cos(30 + A) + Cos(60 - A) Sin(30 + A) = 1

Answer 1

sinX*cosY + cosX*sinY = sin(X+Y)
here, if X = 60-A  and  Y = 30+A
therefore,Sin(60 - A) Cos(30 + A) + Cos(60 - A) Sin(30 + A) 
= Sin(60-A + 30+A) = Sin(90) = 1