2. Consider the following function of three variables: f(x, y, z) = xey + yez+ zex (a) Find the gradient of the function. (b) Find the directional derivative of the function at the point P(0, 0, 1) in the direction of the vector v = 31-91. (c) Find the maximum value of the directional derivative at the point Q(1, 1, 1)