In a controlled chemical synthesis, the rate of production of a particular polymer, R kg h−1R\text{ kg h}^{-1}R kg h−1, is modelled by the equation:
R=20.4−20.0e−0.5t−0.4e0.25t R = 20.4 - 20.0e^{-0.5t} - 0.4e^{0.25t} R=20.4−20.0e−0.5t−0.4e0.25twhere ttt is the time in hours since the reaction vessel was activated.
Determine the maximum production rate predicted by the model, giving your answer to one decimal place. Fully justify your answer.
Derive an expression for the total mass of polymer produced, M kgM\text{ kg}M kg, in terms of ttt.
After 15 hours, the total mass of polymer produced was measured to be 200 kg. Comment on the accuracy of the model.
864 exam-style questions on Edexcel A Level Maths Integration, covering 11.1 Integrating Standard Functions, 11.2 Integrating f(ax + b), 11.3 Using Trigonometric Identities, 11.4 Reverse Chain Rule, 11.5 Integration by Substitution, 11.6 Integration by Parts, 11.7 Partial Fractions, 11.8 Finding Areas, 11.9 The Trapezium Rule, 11.10 Solving Differential Equations, and 11.11 Modelling with Differential Equations. Each one has a worked solution and a mark scheme showing where the marks go.