Find the rate of change of the area of a circle with respect to its radius. How fast is the area changing with respect to the radius when the radius is 3 cm?

Explanation

The area of a circle (A) with radius (r) is given by,


`A=pi r^{2}`


Now, the rate of change of the area with respect to its radius is given by,
`

frac{dA}{dr}=frac{d}{dr}(pi r^{2})=2 pi r`


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