Question

Which of the following is true for all values of θ (0° ≤ θ ≤ 90°)?

Options

• cos² θ – sin² θ = 1

• cosec² θ – sec² θ = 1

• sec² θ – tan² θ = 1

• cot² θ – tan² θ = 1

Answer 1

sec² θ – tan² θ = 1

Explanation:

∵ sec² θ = 1 + tan² θ

∴ sec² θ – tan² θ = 1