The value of cos²20° + cos²70° = ?

A. $$\sqrt 2 $$

B. 1

C. $$\frac{1}{3}$$

D. 2

Answer: Option B

Solution(By Examveda Team)

$$\eqalign{ & = {\cos ^2}{20^ \circ } + {\cos ^2}{70^ \circ } \cr & = {\cos ^2}\left( {{{90}^ \circ } - {{70}^ \circ }} \right) + {\cos ^2}{70^ \circ } \cr & = 1 \cr} $$