If sec 4A = cosec (A – 20°), where 4A is an acute angle, find the value of A

Question

If sec 4A = cosec (A &#x2013; 20&#xB0;), where 4A is an acute angle, find the value of A

Philoid · Accepted Answer

sec 4A = cosec (90° - 4A) = cosec (A - 20°)

Therefore,

90° – 4A = A - 20°

110°– 4A = A

5A = 110°

A = 22°