24. Find a unit vector in the direction in which /(x. y)=e) decreases most rapidly at P(2, 3), and find the rate of change of f (x, y) at P in that direction. 25. The temperature at a point (x. y.=) is given by T(x, y.=)=200e -x2 -3)2-922 where 7 is measured in "Cand x, y. : in meters. Find the maximum rate of increase at P(2, -1, 2)