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 one year ago
all edges of a cube are expanding at a rate of 3 centimeters per second. how fast is the volume changing when each edge is (a) 1 cm. (b) 10 cm.
 one year ago
all edges of a cube are expanding at a rate of 3 centimeters per second. how fast is the volume changing when each edge is (a) 1 cm. (b) 10 cm.

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satellite73
 one year ago
Best ResponseYou've already chosen the best response.1looks like a related rate problem fortunately the formula for the volume of a cube is easy, it is \(V(x)=x^3\)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1take the derivative with respect to time and get \[V'=3x^2x'\]

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1you are told \(x'=3\) so this is really \[V'=9x^2\] replace \(x\) by the various values to get \(V'\)

angelarios
 one year ago
Best ResponseYou've already chosen the best response.0dV/dt=9x^2dx/dt ?:)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1i used \(V'\) and \(x'\) instead of \(\frac{dV}{dt}\) and \(\frac{dx}{dt}\) because it was easier for me to write also for you it is easier

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1but in your notation, you have \[V=x^3\] so \[\frac{dV}{dt}=3x^2\frac{dx}{dt}\]

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1this line all edges of a cube are expanding at a rate of 3 centimeters per second tells you that \(\frac{dx}{dt}=3\)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1that means \(\frac{dV}{dt}=3x^2\times 3=9x^2\)

satellite73
 one year ago
Best ResponseYou've already chosen the best response.1let me know if i lost you there

angelarios
 one year ago
Best ResponseYou've already chosen the best response.0So dats da answer?:)
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