The value of following is, cos24° + cos55° + cos125° + cos204° + cos300° ?

A. $$ - \frac{1}{2}$$

B. $$\frac{1}{2}$$

C. 2

D. 1

Answer: Option B

Solution(By Examveda Team)

The value of,
cos24° + cos55° + cos125° + cos204° + cos300°
We know that, cos(180° $$ \pm $$ θ) = -cosθ
⇒ cos24° + cos55° + cos (180° - 55°) + cos (180° + 24°) + cos (360° - 60°)
⇒ cos24° + cos55° - cos55° - cos24° + cos60°
⇒ cos60°
⇒ $$\frac{1}{2}$$