Question

cos 120degree×cos60degree​

Answer 1

-1/4

Step-by-step explanation:

$\cos(120) \times \cos(60)$

cos(180° - 60°) × 1/2

-1/2 × 1/2

Answer 2

Step-by-step explanation:

cos120=cos(90+30)

-sin30

according to problem,

cos120×cos60

-1/2×1/2

-1/4