Given the following function f(x, y) = 3xy + 3x - x^3 - 3y^3 a) Evaluate analytically partialdifferential f/partialdifferential x, partialdifferential f/partialdifferential y, and partialdifferential^2 f/(partialdifferential x partialdifferential y) at x = y = 1. b) Evaluate numerically the same terms given in a) with delta x = delta y = 0.0001