If cos 25° + sin 25° = k, then cos 20° is equal to: – McqOptions

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1.	If cos 25° + sin 25° = k, then cos 20° is equal to:
A.	\(\dfrac{k}{\sqrt 2}\)
B.	\( \pm\dfrac{k}{\sqrt 2}\)
C.	\(-\dfrac{k}{\sqrt 2}\)
D.	None of these
Answer» B. \( \pm\dfrac{k}{\sqrt 2}\)

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