Question

cos A + cos
(120+A) + Cos(120-A) ​

Answer 1

Step-by-step explanation:

Cos A + cos(120° + A) + cos(120 - A)

= Cos A + 2 cos{( 120°+A+120°-A)/2}cos{120°+A-120+A)/2 ………(1) by using the formula

Cos C + cos D = 2 cos (C+D)/2 cos (C-D)/2

(1) reduces to Cos A + 2 cos 120° cos A

= Cos A + 2 (-1/2) cos A

= 0

Answer 2

Answer:

answer is 0

cosA+cos

(120+A)+Cos(120-A)