Final answer:
The correct formula for all solutions of the given trigonometric equation, with a period of 2π, is θ = π/2 + kπ.
Step-by-step explanation:
The trigonometric equation θ = π/2 has only one solution in the interval 0 ≤ θ < 2π. Since the equation has a period of 2π, we need to find a formula that gives all solutions. The correct formula is θ = π/2 + kπ, where k is an integer.