A spherical snowball is melting in the sun. The volume, VVV, of the snowball is decreasing at a constant rate.
Show that the rate of decrease of the snowball's surface area, AAA, is inversely proportional to its radius, rrr.
You may use the following formulae for a sphere:
V=43πr3andA=4πr2 V = \frac{4}{3}\pi r^3 \quad \text{and} \quad A = 4\pi r^2 V=34πr3andA=4πr2Practise Edexcel A Level Maths Differentiation with exam-style questions for A Level Maths. 311 questions covering 9.1 Differentiating sin x and cos x, 9.2 Differentiating exponentials and logarithms, 9.3 The Chain Rule, 9.4 The Product Rule, 9.5 The Quotient Rule, 9.6 Differentiating Trigonometric Functions, 9.7 Parametric Differentiation, 9.8 Implicit Differentiation, 9.9 Using Second Derivatives, and 9.10 Rates of Change, matched to the Edexcel A Level Maths (9MA0) 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.
