(1 point) the radius of a right circular cone is increasing at a rate of 5 inches per second and its height is decreasing at a rate of 3 inches per second. at what rate is the volume of the cone changing when the radius is 20 inches and the height is 40 inches?



Answer :

The rate of change of volume is 418.6  inch³/s .

Rate of increase of radius with time is ( dr/dt ) = 5

rate of decrease of height with time is (dh/dt ) = -3

volume of a cone is given by (V) =  [tex]\frac{1}{3} \pi r^{2}h[/tex]

Now the rate of change of volume  with respect to time is given by dV/dt

∴ dV/dt = d( [tex]\frac{1}{3} \pi r^{2}h[/tex]) / dt

dV/dt =  [tex]\frac{1}{3} \pi (2rh\frac{dr}{dt} + r^{2}\frac{dh}{dt} )[/tex]

value of radius and height when volume is changing are :

r = 20 inches

h = 40 inches

dV/dt = [tex]\frac{1}{3} \pi ([/tex] 2×20×40 ×5 - [tex]20^{2}[/tex]×3 )

dV/dt = [tex]\frac{1}{3} \pi[/tex](1600 - 1200)

dV/dt = (400/3) 3.14

dV/dt = 418.66 inch³/s

So the rate of change of the volume is 418.66 inch³/s.

learn more about rate of change problems here :

https://brainly.com/question/22716418

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