QUESTION 7 (40 marks) The speed, V (km/h), of a car at time t (seconds) is given by 120 + 80 cos 90 V = f(t) = 3-cos 90

[answerhappygod]

Question 7 40 Marks The Speed V Km H Of A Car At Time T Seconds Is Given By 120 80 Cos 90 V F T 3 Cos 90 1 (28.98 KiB) Viewed 22 times

QUESTION 7 (40 marks) The speed, V (km/h), of a car at time t (seconds) is given by 120 + 80 cos 90 V = f(t) = 3-cos 90 where 0 <t < 90. (a) We want to know when the car will reach a certain speed. Solve for the time t in terms of the speed V, and hence find the formula for the inverse function (). (20 marks) (b) Write down the domain off-(0) (5 marks) (c) Plot ft) from t = 0 tot = 90 and then plot /-) on the same axes but only for the values of t in the domain of the inverse function found in (b). (6 marks) (d) Describe the geometric relationship that you can see when you consider both f(t) and S-(.). (3 marks) (e) When will the speed of the car be equal to 40 km/h? Use the inverse function you found in part (a) to help you answer this. (6 marks)