3. A contour diagram for the function z =f(x, y) is drawn below. The level curves are spaced at intervals of z = 1. You are given that f(-1, 2) = 3 and f(0, y) is increasing in y fory > 0. With that, you should be able to identify the z-value for each level curve. (a) Use the contour diagram to find the gradient vector for fat the point (-1, 2). [Hint: the entries of Vf are integers.] (b) The tangent line to the level curve z = 3 is drawn at the point (-1, 2). Find its equation.1.5 - 0.5 - 2 0.5 0 0.5 -0.5