Simplify the expression (1 - cos²(θ)) / sin(θ), assuming sin(θ) ≠ 0.

Start with the expression:
(1 - cos²(θ)) / sin(θ)

Use the Pythagorean identity:
sin²(θ) + cos²(θ) = 1

Subtract cos²(θ) from both sides:
1 - cos²(θ) = sin²(θ)

Replace the numerator with sin²(θ):
sin²(θ) / sin(θ)

Since sin(θ) ≠ 0, one factor of sin(θ) cancels:
sin²(θ) / sin(θ) = sin(θ)

Therefore, the expression simplifies to sin(θ).