Question

Solve 2 tan^-1(cos x) = tan^-1(2 cos x)

Answer 1

2 tan^-1(cosx) = tan^-1(2cosx)

⇒ \(\frac{2cos}{1-cos^2x} = 2cosx\)

⇒ 1 = 1 – cos² x ⇒ 1 = sin²x

⇒ x = \(±\frac{π}{2}.\)