The volume of a sphere of radius [math] is [math].

(a) Write a differential formula that estimates the change in volume of a sphere when the radius changes from [math] to [math]. Enter [math] as r0 and [math] as dr.
[math] = help (formulas)

(b) Write a differential formula that estimates the change in volume of a sphere when the radius changes from [math] to [math].
[math] = help (formulas)

(c) Use a differential to estimate the change in volume of a melting spherical snowball when the radius changes from [math] to [math].
[math] = [math]