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soty2013

  • 3 years ago

Find the rate of change of the area of a circle per second with respect to its radius r when r = 5 cm.

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  1. soty2013
    • 3 years ago
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    @ParthKohli

  2. ParthKohli
    • 3 years ago
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    Differentiate \(\pi r^2\) with respect to \(r\).

  3. ParthKohli
    • 3 years ago
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    When you find \(f'(r)\), find \(f'(5)\)

  4. soty2013
    • 3 years ago
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    Thanks

  5. ParthKohli
    • 3 years ago
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    The answer turns out to be the circumference.

  6. BAdhi
    • 3 years ago
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    Actually shouldn't it be like this, $$A=\pi r^2$$ Since rate of change is associated with 'time' differentiation with respect to 't'- time, $$\frac{dA}{dt}=\pi\frac{dr^2}{dt}=2\pi r\frac{dr}{dt}$$ rate of change in radius should be given

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