The volume of a closed cylinder of base radius \(x\text{ cm}\) and height \(h\text{ cm}\) is \(500\text{ cm}^3\).

(i) Express \(h\) in terms of \(x\).

(ii) Show that the total surface area of the cylinder is given by \(A=2\pi x^2+\dfrac{1000}{x}\text{ cm}^2\).

(iii) Given that \(x\) can vary, find the stationary value of \(A\) and show that this value is a minimum.