Question

If tanθ.tan4θ=1, then find the value of θ.

Answer 1

Tanθ × Tan4θ = 1

⇒ Tanθ = 1/Tan4θ

⇒ Tanθ = Cot4θ    (since : Tan4θ = 1/Cot4θ)

⇒ Tanθ = Tan(90° - 4θ)

⇒ θ = 90° - 4θ

⇒ 5θ = 90°

⇒ θ = 90°/5 = 18°

Answer 2

See the answer... below