Posted by Jax on Monday, November 12, 2012 at 7:53pm.
A spherical ball is being filled with air. When the radius r=9cm, the radius is increasing at a rate 4 cm/s. How fast is the volume changing at this time (leave your answer approximate)?

Calculus  sam, Monday, January 7, 2013 at 4:03pm
V= 4/3 pi r^3
V= 4pi r^2 dt/dv
4= 4 pi (9)^2 dt/dv
1/81 pi