Question

Sin(pi/12)cos(11pi/12) + cos (pi/12) sin (11pi/12)

Answer 1

Sin a * cos b + sin b * cos a = sin(a+b)
=> Sin(pi/12)cos(11pi/12) + cos (pi/12) sin (11pi/12) = sin(pi/12 + 11pi/12) = sin pi = 0