Determine the diameter of a close cylindrical tank having a volume of 11.3 cubic meter that would give the smallest surface area

Answer 1

1/4 d^2 h = 11.3
h = 45.2/d^2
a = π/2 d^2 + πdh = π/2 d^2 + 45.2π/d
da/dd = πd - 45.2π/d^2
da/dd=0 at d=3.56