Question

find the value of cos 12° + cos 84° + cos 156° + cos 132°​

Answer 1

Answer:

-0.5

Step-by-step explanation:

cos 12°+ cos 84°+ cos 156° +cos 132°

=cos 12°+cos

=-0.5

Answer 2

Answer:

please mark me as the brainlist.

Step-by-step explanation:

$\cos12 \cos84cos156cos132 \\ ( \cos12 + \cos132) + (cos84 + \cos 156) \\ 2 \cos72 \cos60 + 2 \cos120 \ \cos36 \\ \cos72 - \cos36 = \sin18 \ - \cos36 \\ \sqrt{5} - 1 \div 4 - \sqrt{5} + 1 \div 4 \\ = \frac{ - 1}{2} ans..$