Calculus - Related Rate 1

2013-12-01 10:00 pm
A spherical snowball melts at a rate proportional to its surface area. Show that the rate of change of the radius is a constant.

回答 (1)

2013-12-01 10:06 pm
✔ 最佳答案
V = (4/3)πr^3

A = 4πr^2

We know that dV/dt = K(4πr^2) where K is a constant

On the other hand, dV/dt is also equals to dV/dr * dr/dt

= 4πr^2 * dr/dt

So, 4πr^2 * dr/dt = K(4πr^2)

or dr/dt = K

That is, the rate of change of the radius is a constant


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