A = 2πr^2 + 2πrh = 2π(r^2 + 500/(πr)) dA/dr = 2π(2r - 500/(πr^2)) = (4πr^3 - 1000)/πr^2 dA/dr = 0 when r = 5∛(2/π), so h = 10∛(2π)
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