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.
332 exam-style questions on WJEC A Level Maths 3.6 Differentiation (A-level only), covering 3.6.1 Differentiation (A-level only), 3.6.2 Differentiation (A-level only), 3.6.3 Differentiation (A-level only), 3.6.4 Differentiation (A-level only), 3.6.5 Differentiation (A-level only), 3.6.6 Differentiation (A-level only), 3.6.7 Differentiation (A-level only), and 3.6 Differentiation (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.