Suppose that the edge lengths x, y, z of a closed rectangular box are changing at the following rates: dx/dt= 1m/s, dy/dt= -2 m/s, and dz/dt= 0.5 m/s.

At the instant x= 2m, y= 3m, z= 5m, find the rates of change:

a) volume of the box
b) surface area of the box
c) diagonal of the box