A scientist models the activity, AAA MBq, of a radioactive isotope over time, ttt days, using the equation
A=(15t+2)e−0.4t,t≥0 A = (15t + 2)e^{-0.4t}, \quad t \ge 0 A=(15t+2)e−0.4t,t≥0Find, using calculus, the exact value of ttt for which the activity is stationary.
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.
