sin⁴ θ - cos⁴ θ is equal to :

1. sin² θ - 1

2. 1 + cos² θ

3. 2 sin² θ - 1

4. 1 - cos² θ

cot⁴ θ + cot² θ is equal to :

1. 2 cot² θ. cosec² θ

2. tan² θ + tan⁴ θ

3. tan² θ.cosec² θ

4. cosec⁴ θ - cosec² θ

$\dfrac{1}{\text{1 - sin A}}$ is equal to :

1. 1 + sin A

2. sec² A (1 + sin A)

3. sec² A

4. sec² A + sin A

$\dfrac{\text{tan}^2 A}{\text{(sec A + 1)}^2}$ is equal to :

1. $\dfrac{\text{1 + cos A}}{\text{1 - cos A}}$

2. $\dfrac{\text{1 - cos A}}{\text{1 + cos A}}$

3. $\dfrac{1}{\text{1 + cos A}}$

4. $\dfrac{1}{\text{1 - cos A}}$