c) Given that the pro-sure of air at any point (3:, y, z) is P(m,y, z) = e29 (a: + 7.2) - 432:2. At point (1,0, 1), nd the rate of change of the pressure P(:r,y,z) in the direction of i+2j k. Hence, determine the lowest rate of change in pressure P(:r,y, z) and its direction in unit vector. (8 marks)