A solid sphere is dissolving in a chemical solution. The surface area of the sphere, AAA, is decreasing at a constant rate.
Show that the rate of decrease of the radius, rrr, of the sphere is inversely proportional to rrr.
You may use the following formula for the surface area of a sphere: A=4πr2A = 4\pi r^2A=4πr2
Practise Edexcel A Level Maths 9.10 Rates of Change with exam-style questions for A Level Maths. 24 questions, 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.