The height of a maintenance lift, H H\,H metres, relative to the ground floor is recorded over time t t\,t seconds. The height is modelled by the function
H(t)=18−∣3t−21∣ H(t) = 18 - |3t - 21| H(t)=18−∣3t−21∣Sketch the graph of H(t)H(t)H(t), marking the coordinates of any points where the graph intersects the axes and the coordinates of the vertex.
Solve the inequality
18−∣3t−21∣<9 18 - |3t - 21| < 9 18−∣3t−21∣<9181 exam-style questions on OCR (MEI) A Level Maths 1.3 Functions, covering 1.3.1 Operations on polynomials, 1.3.2 Factor theorem, 1.3.3 Definition of a function (A-level only), 1.3.4 Composite functions (A-level only), 1.3.5 Inverse functions and their graphs (A-level only), 1.3.6 The modulus function (A-level only), 1.3.7 Inequalities with a modulus sign (A-level only), and 1.3.8 Functions in modelling (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.