A transport container for radioactive waste is designed as a cuboid with width xxx m, length 2.5x2.5x2.5x m, and height hhh m. The total interior volume of the container must be 500 m3500\text{ m}^3500 m3.
Show that the total surface area of the container, S m2S\text{ m}^2S m2, is given by
S=5x2+1400x S = 5x^2 + \frac{1400}{x} S=5x2+x1400Find dSdx\frac{\text{d}S}{\text{d}x}dxdS.
Hence find the value of xxx for which SSS is stationary, giving your answer to 3 significant figures.
Find d2Sdx2\frac{\text{d}^2S}{\text{d}x^2}dx2d2S and hence verify that the value of xxx found in part (c) gives a minimum value for SSS.
Calculate the minimum surface area of the container, giving your answer to 1 decimal place.
Practise AQA A Level Maths 1.10 G: Differentiation with exam-style questions for A Level Maths. 321 questions covering 1.10.1 The derivative and second derivative, 1.10.2 Differentiating standard functions, 1.10.3 Applications of differentiation, 1.10.4 Product, quotient and chain rules (A-level only), 1.10.5 Implicit and parametric differentiation (A-level only), and 1.10.6 Constructing differential equations (A-level only), matched to the AQA A Level Maths (7357) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
