Find $$\cos \left( { - \frac{{7\pi }}{2}} \right) = ?$$

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

B. 1

C. -1

D. 0

Answer: Option D

Solution(By Examveda Team)

$$\eqalign{ & \cos \left( { - \frac{{7\pi }}{2}} \right) \cr & = \cos 7 \times \frac{{180}}{2} \cr & = \cos 630 \cr & = \cos \left( {2 \times 360 - 90} \right) \cr & = \cos 90 \cr & = 0 \cr} $$