(cos⁴ θ − sin⁴ θ) is equal to :

1. 2 cos² θ + 1

2. 2 cos² θ − 1

3. 2 sin² θ + 1

4. 2 sin² θ − 1

If sec θ + tan θ + 1 = 0, then sec θ − tan θ is equal to :

1. −1

2. 0

3. 1

4. 2