Question

If a snowball melts so that its surface area decreases at a rate of 6 cm2/min, find the rate at which the diameter decreases when the diameter is 11 cm.

Answer 1

what is the formula for the surface area of a sphere?

Answer 2

4

Answer 3

good, but lets write it like this:

diam = 2 times the radius

d = 2r

d^2 = 4r^2 sooo

S = pi d^2

Answer 4

now, just take an implicit derivative