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Now some of you might have seen this problem in Fundamentals of Physics Extended Fifth Edition. Please give me some hints.

- Thread starter Hyperreality
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Now some of you might have seen this problem in Fundamentals of Physics Extended Fifth Edition. Please give me some hints.

- #2

HallsofIvy

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A cylinder of radius r and height h has three surfaces: the top and bottom, each of area [pi]r

V= [pi]r

the surface area as A= 2[pi](r

Differentiate with respect to r, set equal to 0 and solve for r.

You will get a formula for r that depends on V. Substitute for V with the formula above and see what happens.

- #3

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First solution:

A minimum area is obtained when h = r for A = [pi] r^2 + 2[pi] rh.

Second solution:

A minimum surface area is obtained when h = 2r.

Can anyone please explain the result to me?

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Second solution: when A = 2[pi] r^2 + 2[pi] rh

- #5

HallsofIvy

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the "lateral surface" area is 2[pi]rh and each end has area [pi]r

A= [pi]r

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