Suppose that the radius r of a right circular cone of fixed height h = 30 cm is increasing at a rate 10 cm/s. How fast is the volume increasing when r = 15? Give your answer correct to two decimal places.

Answer 1

from the information ...

V =30πr^2
dV/dt = 60πr dr/dt
= 60π(15)(10)
= 9000π cm^3/sec
= .... (you do the button-pushing for the required accuracy)

Answer 2

If cone not cylinder
then
V = (1/3) h pi r^2
V = 10 pi r^2
The rest is the same

Answer 3

sorry, I should really read more carefully,