The value of expression cos²45° + cos²135° + cos²225° + cos²315° is:

A. 2

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

C. $$\frac{3}{2}$$

D. 1

Answer: Option A

Solution(By Examveda Team)

cos²45° + cos²135° + cos²225° + cos²315°
= (cos²45° + cos²315°) + (cos²135° + cos²225°)   [Here cos²α + cos²β = 1, where α + β = 360°]
= 1 + 1
= 2