∂f/∂x = 2xy, ∂f/∂y = x^2 + 3y^2. The slope of the tangent line to the surface z = f(x, y) in the x-direction is 2xy, and in the y-direction is x^2 + 3y^2.
∂f/∂x = y, ∂f/∂y = x. These are the partial derivatives of f(x,y) = xy, not f(x,y) = x^2y + y^3.
Baroque art features strong contrasts, while Rococo art prefers more subtle transitions
Baroque art is generally larger in scale than Rococo art