in a right circular cylinder of height 2 meters, if the volume is increasing at 10 m^3/min how fast is the radius of the cylinder increasing when the radius is 4in?

Respuesta :

Given dimensions:

Height of the cylinder = 2 m

Volume is increasing at a rate of = 10 m³/min

Radius = 4 inches

Converting radius in meters.

1 inch = 0.0254 meters

4 inches = [tex]4\times0.0254=0.1016[/tex] meters

[tex]\frac{dv}{dt}=10[/tex]

we have to find, [tex]\frac{dr}{dt}=?[/tex]

Volume of the cylinder is given by [tex]\pi r^{2} h[/tex]

= [tex]\pi r^{2} *2 = 2\pi r^{2}[/tex]

Now differentiating with respect to 't'

[tex]\frac{dv}{dt} = \frac{d}{dt} (2\pi r^{2})[/tex]

[tex]\frac{dv}{dt} = 2\pi (2r)(\frac{dr}{dt})[/tex]

[tex]10=2\pi (2*0.1016)\frac{dr}{dt}[/tex]

[tex]10=2*3.14(0.2032)\frac{dr}{dt}[/tex]

[tex]\frac{dr}{dt}=\frac{10}{1.276}[/tex]

= 7.83 meter per minute.