1. Find the values of each cosine term:
cos 120° = -1/2
cos 240° = -1/2
cos 180° = -1
cos 60° = 1/2
2. Substitute the values into the expression:
cos 120° cos 240° cos 180° cos 60° = (-1/2) (-1/2) (-1) * (1/2)
3. Calculate the result:
= 1/16 * (-1)
= -1/16
Therefore, the value of cos 120° cos 240° cos 180° cos 60° is -1/16.
