Question

Find the value of cos 120° cos 240° cos 180° cos 60°.

• A. -1/8
• B. 1/2
• C. 1/4
• D. 1/16

Answer 1

Answer:

A. -1/8

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.