om of the pap 20. The volume of a sphere is V = mr) and the surface area of a sphere is S = 4ar. that the le ( x4 a) Use differentials to estimate the change in surface area of a sphere if the radius changes from 3 to 3,1 b) Compare this to the actual change in surface area c) Use differentials to estimate the change in volume of a sphere if the radius changes from 3 to 3.1