Write the value of cosec2 θ (1 + cos θ)(1 – cos θ).
Consider cosec2 θ (1 + cos θ)(1 – cos θ) = cosec2 θ (1 – cos2 θ)
= cosec2 θ sin2 θ
(∵ sin2 θ + cos2 θ = 1)
= 1