Calculus HARD NEED HELP
posted by Kris .
The volume of a cone of radius r and height h is given by V=(1/3)pir^2h. If the radius and the height both increase at a constant rate of 2cm/s at which rate in cubic cm/s is the volume increasing when the height is 8cm and the radius is 6cm.
So The answer is 108 pi.
Here's what I did. I thought that dr/dt=2 and dh/dt=2 looking for dv/dt when h=8 and r=6
so dv/dt=(pi/3)*36*2 + (2pi/3)*6*8*2
I got 88pi....that is wrong....what did I do wrong :'(
Thanks

Calculus HARD NEED HELP 
Reiny
I also got 88π
Respond to this Question
Similar Questions

Calculus
The volume of a cone of radius r and height h is given by V=1/3pir^2h. If the radius and the height both increase at a constant rate of 1/2 centimeter per second, at what rate, in cubic centimeters per second, is the volume increasing … 
calcrelated rates
"The volume of a cone of radius r and height h is given by V=1/2(pi)(r^2)(h)If the radius and the height both increase at a constant rate of .5 cm per second at WHAT RATE in cubic cm per second, is the volume increasing when the height … 
Calculus
The volume of a cone of radius r and height h is given by V=(1/3)pir^2h. If the radius and the height both increase at a constant rate of 2cm/s at which rate in cubic cm/s is the volume increasing when the height is 8cm and the radius … 
Calculus
The volume of a cone of a radius r and height h is given by V=(3.14/3)(r^2)(h). If the radius and the height both increase at a constant rate of .5 cm per second, at what rate, in cubic cm per second, is the volume increasing when … 
AP calculus AB
At the instant when the radius of a cone is 3 inches, the volume of the cone is increasing at the rate of 9 pi cubic inches per minute. If the height is always 3 times the radius, find the rate of change of the radius at that instant. 
calculus
At the instant when the radius of a cone is 3 inches, the volume of the cone is increasing at the rate of 28.27433388 cubic inches per minute. If the height is always 3 times the radius, find the rate of change of the radius at that … 
calculus help please
At the instant when the radius of a cone is 3 inches, the volume of the cone is increasing at the rate of 9 pi or 28.27433388 cubic inches per minute. If the height is always 3 times the radius, find the rate of change of the radius … 
calculus
The radius of a cone increases at the rate of 0.3 inches per minute, but the volume remains constant. At what rate does the height of the cone change when the radius Is 4 inches and the height is 15 inches? 
calculus inverted cone
A container in the shape of an inverted cone has radius 6 ft and height 12 ft. It is being drained at 2〖ft〗^3/min. Find the rate of change of the height of the liquid in the cone when the height is 3 feet. The ratio of … 
math
the radius r of a right circular cone is increasing at a rate of 2cm/min.the height h of the cone is related to the radius by h=3r.find the rate of change of the volume when r=6cm