Question

cos 2θ = sin θ, ∴ θ = ______.

विकल्प

• 0°

• 90°

• 60°

• 30°

Answer 1

cos 2θ = sin θ, ∴ θ = 30°.

Explanation:

cos 2θ = sin θ, using identity cos⁡ 2θ = 1 − 2 sin²θ

we get 2 sin² θ + sin θ − 1 = 0.

θ = `1/2`​

θ = 30°