If sec 4A = cosec (A – 10°) and 4A is acute then A = ?

We are given that: sec 4A = cosec (A – 10°)

We can rewrite it as: cosec (90° – 4A) = cosec (A – 10°)


On comparing both sides, we get,


90° – 4A = A – 10 °


A + 4A = 90° + 10°


5A = 100°


A = 20°

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