If sec (7α - 60°) = cosec (15° - 4α) then the value of cosα .
Answer & explanation
Correct answer: option 4
[Concept: sec A = cosec B, when A + B = 90°]
Therefore,
(7α - 60° + 15° - 4α) = 90°
3α = 135°
α = 45°
Put this value in find →
⇒ cos45° = \(\frac{1}{\sqrt {2}}\)