The concentration CCC, in mg L−1\text{mg L}^{-1}mg L−1, of a certain chemical in a reaction is modeled by the equation C=12.5e−0.8tC = 12.5 e^{-0.8t}C=12.5e−0.8t, where ttt is the time in hours after the start of the reaction. Determine the rate of change of the concentration, in mg L−1h−1\text{mg L}^{-1}\text{h}^{-1}mg L−1h−1, at the instant when the concentration is exactly 2.4 mg L−12.4 \text{ mg L}^{-1}2.4 mg L−1.
375 exam-style questions on AQA A Level Maths 1.10 G: Differentiation, 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). Each one has a worked solution and a mark scheme showing where the marks go.