posted by Herb .
What is the rate of change of the volume of a ball (V=(4/3)pi r^3) with respect to the radius when the radius is r=2?
LOL, it is the surface area 4 pi r^2
4 pi r^2 dr = dV
dV/dr = 4 pi r^2
dV/dt = 4 pi r^2 dr/dt