(i)[3]
Show that the cuboid's total surface area, $A\text{ cm}^2$, can be written as $A = 6x^2 + \frac{768}{x}$.
(ii)[5]
Given that $x$ can vary, find the stationary value of $A$ and determine its nature.
Mathematics 9709 · AS & A Level · Differentiation
Differentiation — practice question
The base of a cuboid has side lengths $x\text{ cm}$ and $3x\text{ cm}$. Its volume is $288\text{ cm}^3$.