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.
480 exam-style questions on AQA A Level Maths 1.11 H: Integration, covering 1.11.1 Fundamental Theorem of Calculus, 1.11.2 Integrating standard functions, 1.11.3 Definite integrals and areas, 1.11.4 Integration as the limit of a sum (A-level only), 1.11.5 Integration by substitution and by parts (A-level only), 1.11.6 Integration using partial fractions (A-level only), 1.11.7 Differential equations with separable variables (A-level only), and 1.11.8 Interpreting solutions of differential equations (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.