The temperature at the point (x, y) on a metal plate is T(x, y) = 400e^-(x2+y)/2, x ≥ 0, y ≥ 0.
(a) Use a computer algebra system to graph the temperature distribution function.
(b) Find the directions of no change in heat on the plate from the point (3, 5).
(c) Find the direction of greatest increase in heat from the point (3, 5).