Find the surface area of the unit sphere s represented parametrically by φ: d → s ⊂ double-struck r3, where d is the rectangle 0 ≤ θ ≤ 2π, 0 ≤ ϕ ≤ π and φ is given by the following equations. x = cos(θ) sin(ϕ), y = sin(θ) sin(ϕ), z = cos(ϕ). note that we can represent the entire sphere parametrically, but we cannot represent it in the formz = f(x, y).