Related Rated: The Volume of a cube is decreasing at a constant rate of 10 cubic centimeters per minute. What is the rate of change, in square centimeters per minute of the surface area of the cube at the instant when the length of each edge of the cube id 5 cm?

Question

fanduekisses · Answer

So will I first have to find a relationship between the surface area and the volume of a cube?

anonymous · Answer

$$\prod69_{t}^{h}.dsov rot =21$$

fanduekisses · Answer

what?

anonymous · Answer

wait math are u in

anonymous · Answer

lol srry

anonymous · Answer

lol cant remember im in cal bc v4

anonymous · Answer

sorry

surry99 · Answer

you need expressions for the volume of the cube and surface area of the cube to start

fanduekisses · Answer

$$v=x^{3}$$
$$SA= 6x^{2}$$
x= edges in a cube

fanduekisses · Answer

$$\frac{dv}{dt}=x^2*\frac{dx}{dt}$$
$$\frac{da}{dt}=12*x*\frac{dx}{dt}$$

surry99 · Answer

yes...so from the first equation you can get dx/dt and plug that in to the second to get da/dt

fanduekisses · Answer

ok let me try that ^_^

fanduekisses · Answer

yay I got -8 cm^2 ^_^

surry99 · Answer

-8 cm^2/min

fanduekisses · Answer

Yeah I forgot about the time :) thanks so much ^_^

surry99 · Answer

you are very welcome!