1. First Partial Derivatives: The plane x = 2 intersects the graph of z = f(x, y) = xy + 5x in a curve, C. 2. (a) Calculate oat (x, y) = (2, 3). (b) Find a parametrization of the tangent line to the curve C at the point where y = 3. Mixed Partial Derivatives: In the contour plot below dark shades represent small values of the function and light shades represent large values of the function. What is the sign of the mixed partial derivative? y 2.0F 1.5 1.0 0.5 0.0 0.0 0.5 1.0 1.5 2.0 X