Mark the correct alternative in the following:

If , then is equal to

Mark the correct alternative in the following:

If π < x < 2 π, then is equal to

Mark the correct alternative in the following:

If , and if , then y is equal to

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