Posted by Anonymous on .
a spherical balloon is inflated with gas at the rate of 500 cubic centimeters per minute. how fast is the radius of the balloon increasing at the instant the radius is 30 centimeters?

Calculus 
drwls,
The vloume increase rate is dV/dt = 500
V = (4/3) pi R^3
dV/dt = (12/3)pi R^2 dR/dt
= 4 pi R^2 dR/dt
You can use that equation to compute the dR/dt expansion rate for any value of R.
Note that that dV/dt equals the instantaneous surface area times dR/dt. 
Calculus 
Anonymous,
r=30cm
500=4 pi R^2 dR/dt
500=11309.7336 dR/dt
dR/dt = .0442cm/min