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anonymous

  • 5 years ago

the radius of a circle is decreasing at a constant rate of .1 centimeter per second. in terms of circumference C, what is the rate of change of the area of the circle, in square centimeters per second?

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  1. anonymous
    • 5 years ago
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    yup. then mukltiply by whatever coefficents there are for your 4 numbers

  2. anonymous
    • 5 years ago
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    A = pi*r^2; dA/dt = 2*pi*r*dr/dt. We know dr/dt = 0.1cm/sec. We need to know the 'r' at which we want to determine the change in area (dA/dt) and stick that into the equation: dA/dt = 2*pi*r*dr/dt

  3. anonymous
    • 5 years ago
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    wait, why do you multiply dr/dt

  4. anonymous
    • 5 years ago
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    seocnd statement after Area formula

  5. anonymous
    • 5 years ago
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    This is a related rate problem. The dA/dt is related to the dr/dt, which is a given.

  6. anonymous
    • 5 years ago
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    Yes, you want dA/dt, which equals 2*pi*r*dr/dt

  7. anonymous
    • 5 years ago
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    so.. the anser is -.1(2pirR)

  8. anonymous
    • 5 years ago
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    WAIT NO

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