Trigonometrical Functions

Matching exercise

    
Match the items on the right to the items on the left.
2cos x cos y
– 2sin x sin y
2sin x cos y
2 cos x sin y
cos ( x + y) + cos ( x – y)
cos (x + y) – cos (x – y)
sin (x + y) + sin (x – y)
2 cos x sin y = sin (x + y) – sin (x – y)