The value of cos220° + cos270° = ?
A. $$\sqrt 2 $$
B. 1
C. $$\frac{1}{3}$$
D. 2
Answer: Option B
Solution (By Examveda Team)
$$\eqalign{ & = {\cos ^2}{20^ \circ } + {\cos ^2}{70^ \circ } \cr & = {\cos ^2}\left( {{{90}^ \circ } - {{70}^ \circ }} \right) + {\cos ^2}{70^ \circ } \cr & = 1 \cr} $$This Question Belongs to Arithmetic Ability >> Trigonometry
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