The value of (1- cos θ)(1+ cos θ)(1+ cot 2 θ) when θ= (π/15) is

Question

The value of (1- cos θ)(1+ cos θ)(1+ cot 2 θ) when θ= (π/15) is (A) 1 (B) (1/2) (C) (-1/√3) (D) 2

Tardigrade Admin · Accepted Answer

(1- cos θ)(1+ cos θ)(1+ cot 2 θ) =(1- cos 2 θ)( textcosec2 θ) = sin 2 θ ⋅ textcosec2 θ =1, ∀ θ

Q. The value of $(1 - cos θ) (1 + cos θ) (1 + cot^{2} θ)$ when $θ =$ $\frac{π}{15}$ is