Question 868034
My answer is: 
V(t)=4t(3-t)
Rate of change of volume of V(t) is V'(t) 
V(t)=4t(3-t)
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V(t) = 12t-4t^2 
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V(t+D) = 12(t+D) - 4(t+D)^2
= 12t+12D -4(t^2+ 2tD + D^2)
= 12t +12D -4t^2 -8tD -4D^2

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 [V(t+∆t)- V(t)] / ∆t
= [ 12D - 8(tD)  -4(D)^2]/D
=  [12 - 8t - 4D]
lim of V(t)/Dt as V goes to 0 = 12-8t 
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Cheers,
Stan H.
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