A spherical snowball is melting in such a way that its radius is decreasing at a rate of 0.2 cm/min. At what rate is the volume of the snowball decreasing when the radius is 17 cm. (Note the answer is a positive number).

Respuesta :

Answer:

726.34 cm/min

Step-by-step explanation:

Volume of a sphere:

The volume of a sphere is given by the following equation:

[tex]V = \frac{4\pi r^3}{3}[/tex]

In which r is the radius.

Implicit derivatives:

This question is solving by implicit derivatives. We derivate V and r, implicitly as function of t. So

[tex]\frac{dV}{dt} = 4\pi r^2 \frac{dr}{dt}[/tex]

A spherical snowball is melting in such a way that its radius is decreasing at a rate of 0.2 cm/min.

This means that [tex]\frac{dr}{dt} = -0.2[/tex]

At what rate is the volume of the snowball decreasing when the radius is 17 cm.

This is [tex]\frac{dV}{dt}[/tex] when [tex]r = 17[/tex]

[tex]\frac{dV}{dt} = 4\pi r^2 \frac{dr}{dt}[/tex]

[tex]\frac{dV}{dt} = 4\pi*(17)^2*(-0.2)[/tex]

[tex]\frac{dV}{dt} = -726.34[/tex]

This means that the volume of the snowball is decreasing at a rate of 726.34 cm/min when the radius is 17 cm.