Consider the following. f(x, y) = 9x² + 4y 2 C = 52, P(2, −2) (a) Find the gradient of the function at P. Vf(2,-2) = (b) Find a unit vector that is normal to the level curvef(x, y) = c at P. (c) Find the tangent line to the level curve f(x, y) = c at P. (d) Sketch the level curve, the unit normal vector, and the tangent line in the xy-plane. y 6- 6 y x -6 -4 -2 4 6 -6 -4 2 4 -6 y 2 y x x -6 -4 2 2 4 6 -6 -4 2 2 4