pg. 801, #33

The radius of a right circular cylinder is decreasing at a rate of 1.2 cm/s while its height is increasing at a rate of 3 cm/s. At what rate is the volume of the cylinder changing when the radius is 80 cm and the height is 150 cm?

Solution:

Since the volume of the cylinder is , we have

When r = 80 and h = 150 we have