If cos 2 θ = sin 4 θ, where 2θ and 4θ are acute angles, find the value of θ .

Question

Philoid · Accepted Answer

We are given that: cos 2θ = sin 4θ

∴We can rewrite it as: sin (90° - 2θ) = sin 4θ

On comparing both sides, we get,

90° - 2θ = 4θ

⇒ 6θ = 90°

⇒ θ = 15°