Question

express as a product cos 35 +cos 75​

Answer 1

Answer:

sin C + sin D = 2 sin [(C + D)/2] cos [(C - D)/2]

sin C - sin D = 2 cos [(C + D)/2] sin [(C - D)/2]

cos C + cos D = 2 cos [(C + D)/2] cos [(C - D)/2]

cos C - cos D = -2 sin [(C + D)/2] sin [(C - D)/2]