A cuboid has width 2x 2x\,2x cm, height x x\,x cm and depth y y\,y cm.
The volume of the cuboid is 600 cm3^33, and its surface area is S S\,S cm2^22.
Show that S=4x2+1800xS = 4x^2 + \dfrac{1800}{x}S=4x2+x1800.
Determine the value of x x\,x for which the surface area of the cuboid is a minimum, giving your answer to 3 significant figures.
Find, to the nearest integer, the minimum value of SSS.
43 exam-style questions on WJEC A Level Maths 1.7 Differentiation, covering 1.7.1 Differentiation, 1.7.2 Differentiation, 1.7.3 Differentiation, 1.7.4 Differentiation, 1.7.5 Differentiation, and 1.7.6 Differentiation. Each one has a worked solution and a mark scheme showing where the marks go.