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∣<918 - |3t - 21| < 918−∣3t−21∣<9
Practise Edexcel A Level Maths Functions and Graphs with exam-style questions for A Level Maths. 100 questions covering 2.1 The Modulus Function, 2.2 Functions and Mappings, 2.3 Composite Functions, 2.4 Inverse Functions, 2.5 y=|f(x)| and y=f(|x|), 2.6 Combining Transformations, and 2.7 Solving Modulus Problems, matched to the Edexcel A Level Maths (9MA0) specification and written in Paper 1, Paper 2 and Paper 3 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.