Jawabanmu

2014-06-04T11:16:46+07:00
L = x² + 4xt
27 = x² + 4xt
t = (27 - x²)/4x
V = La . t = x² . (27 - x²)/4x =  (27x - x³)/4
V' = 0
27 - 3x² = 0
x = 3
Volume maksimal = (27x - x³)/4 = (81 - 27)/4 = 54/4 = 13,5 
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