The value of cos² x + cos² y – 2cos x × cos y × cos (x + y) is

The value of cos² x + cos² y – 2cos x × cos y × cos (x + y) is

A

sin (x + y)

B

sin² (x + y)

C

sin³ (x + y)

D

sin4 (x + y)

Answer:

The correct option is B. sin² (x + y)

Note