A physicist models the intensity of radiation, III, at a distance x x\,x metres from a point source using the equation
I=25x3+0.4x,x≥1I = \frac{25}{x^3} + 0.4^x, \quad x \ge 1I=x325+0.4x,x≥1
Find an expression for the rate of change of radiation intensity with respect to distance, dIdx\dfrac{dI}{dx}dxdI.
Practise Edexcel A Level Maths 9.2 Differentiating exponentials and logarithms with exam-style questions for A Level Maths. 23 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.