Mark the correct alternative in the following:

If and x lies in the IV quadrant, then the value of cos x is

Mark the correct alternative in the following:

If x = r sin θ cos ϕ, y = r sin θ sin ϕ and z = r cos θ, then x² + y² + z² is independent of

Mark the correct alternative in the following:

If , then x is equal to

Mark the correct alternative in the following:

If , then is equal to

Mark the correct alternative in the following:

sin⁶ A + cos⁶ A + 3 sin² A cos² A =