Mathematics 4024 · O Level · Sketching curves

Sketching curves — practice question

A cuboid is of height $h$ cm and has a square base with edge $x$ cm. Its volume is $60\text{ cm}^3$.
(a)[2]

Show that the cuboid's surface area, $A\text{ cm}^2$, is given by $A = 2x^2 + \frac{240}{x}$.

(b)[2]

Fill in the table for $A = 2x^2 + \frac{240}{x}$.

(c)[3]

On the grid, sketch the graph of $A = 2x^2 + \frac{240}{x}$ for $1 \leq x \leq 8$.

(d)[1]

Find the least possible surface area of the cuboid.

(e)[3]

The cuboid has a surface area of $120\text{ cm}^2$. The height of the cuboid exceeds the length of the edge of its base. Find the dimensions of the cuboid.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: $h = \dfrac{60}{x^2}$

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI