what is the value of Sin(A+3B) + Sin(3A+B) / Sin 2A+2B? Prove step by step.

{sin (A+3B)+sin (3A+B)}/SIN 2(A+B)

#SIN C +SIND = 2 SIN  (C+D)/2 * COS (C-D)/2   IS THE FORMULA

#{2SIN (A+3B+3A+B)/2 * COS (A+3B-3A-B)/2} / SIN 2(A+B)

#[2 SIN 2(A+B) *COS (B-A) ] / SIN 2(A+B)

#2 COS (B-A)  IS THE ANS