The circumference of the circle is increasing at a rate of 0.5 meters per minute. What's the rate of change of the area of the circle when the radius is 4 meters?

Respuesta :

Answer:

2 meter square per minute

Step-by-step explanation:

Given the circumference is of the circle is increasing at a rate of 0.5 m/minute

We know that C = 2πr

We know that the area of the circle(A) = π[tex]r^2[/tex]

Let π=a

[tex]r=\frac{C}{2a}[/tex]

A = a [tex](\frac{C}{2a})^2[/tex]

[tex]A=\frac{C^2}{4a}[/tex]

Differentiate both sides with respect to time

[tex]\frac{dA}{dt}=\frac{C}{2a}\frac{dC}{dt}[/tex]

C at r= 4 is C = 8a

Given [tex]\frac{dC}{dt}[/tex] = 0.5

[tex]\frac{dA}{dt}=\frac{8a}{4a}[/tex] = 2