The pressure, PPP kPa, inside a leaking decompression chamber ttt minutes after the leak is first detected, is modelled by the differential equation
dPdt=−k(P−100)2 \frac{\text{d}P}{\text{d}t} = -k(P - 100)^2 dtdP=−k(P−100)2where kkk is a positive constant and P>100P > 100P>100.
Given that the pressure in the chamber:
Solve the differential equation to show that, according to the model,
P=at+bct+d P = \frac{at + b}{ct + d} P=ct+dat+bwhere a,b,ca, b, ca,b,c and ddd are integers to be found.
Hence find, according to the model, the time taken for the pressure in the chamber to reach 150150150 kPa. Give your answer to the nearest minute.
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.