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Mimi_x3

  • 4 years ago

The volume of a sphere radius r increases at 12pi cm^3/minute by inflation. What is the rate of growth of its surface area?

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  1. Mimi_x3
    • 4 years ago
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    Noo..? This is a maths question.

  2. imranmeah91
    • 4 years ago
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    This is what's called related rate problem

  3. Mimi_x3
    • 4 years ago
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    rate of change.

  4. imranmeah91
    • 4 years ago
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    volume of sphere = 4/3 Pi r^3

  5. moneybird
    • 4 years ago
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    |dw:1324353965977:dw|

  6. Mimi_x3
    • 4 years ago
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    I know, i got stuck, there's not enough info :/

  7. moneybird
    • 4 years ago
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    first find the derivative of V first

  8. Mimi_x3
    • 4 years ago
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    I already know. I got stuck in dA/dt = 8pi3*dr/dt There's not enough info.

  9. joemath314159
    • 4 years ago
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    your missing the rate that the radius is increasing.

  10. joemath314159
    • 4 years ago
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    youre*

  11. Mimi_x3
    • 4 years ago
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    I found that the radius is sqrt(3)

  12. joemath314159
    • 4 years ago
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    how did you come about that? there is no volume given

  13. moneybird
    • 4 years ago
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    i mean the derivative of volume

  14. imranmeah91
    • 4 years ago
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    write equation relating volume to surface area v= 4/3 Pi r^3 S= 4 Pi r^2 v= s/3 r dv/ds= 1/3r dv= 1/3 r ds

  15. joemath314159
    • 4 years ago
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    We would still need r though right? or do you think they want the answer in terms of r?

  16. joemath314159
    • 4 years ago
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    boo i already gave you a medal lolol

  17. Hero
    • 4 years ago
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    Mimi skipped basic math and went straight to calculus.

  18. Mimi_x3
    • 4 years ago
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    Shut up Hero, people don't need to know that i dont know basic maths. v= s/3r? where did that come from?

  19. imranmeah91
    • 4 years ago
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    *minor correction v= 4/3 Pi r^3 S= 4 Pi r^2 v= (s r)/3 dv/ds= r/3 dv= r/3 ds (12*3 Pi)/r= ds

  20. Mimi_x3
    • 4 years ago
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    ty.

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