The value of a car is modelled using the formula V=17100e−0.2t+2000V = 17100e^{-0.2t} + 2000V=17100e−0.2t+2000
Find the initial value of the car.
Given the model predicts that the value of the car is decreasing at a rate of £1000 per year at the instant when t=Tt = Tt=T, (i) Show that 3420e−0.2T=10003420e^{-0.2T} = 10003420e−0.2T=1000 and (ii) find the age of the car at this instant, giving your answer in years and months to the nearest month.
104 exam-style questions on OCR A Level Maths 1.6 Exponentials and Logarithms, covering 1.6.1 Properties of the exponential function, 1.6.2 Gradient of e^(kx) (A-level only), 1.6.3 Definition of the logarithm, 1.6.4 The natural logarithm function, 1.6.5 ln x as inverse of e^x, 1.6.6 Laws of logarithms, 1.6.7 Equations involving exponentials, 1.6.8 Reduction to linear form, and 1.6.9 Modelling using exponential functions. Each one has a worked solution and a mark scheme showing where the marks go.