A climatologist is testing four different mathematical models for the atmospheric temperature TTT (in ∘C^\circ\text{C}∘C) as a function of time ttt (in years), where the domain for each function is t∈Rt \in \mathbb{R}t∈R.
Which of the following models does not have an inverse function?
T(t)=0.5t+14.2T(t) = 0.5t + 14.2T(t)=0.5t+14.2
T(t)=(t−2)3+8T(t) = (t - 2)^3 + 8T(t)=(t−2)3+8
T(t)=15−3cos(πt12)T(t) = 15 - 3\cos\left(\dfrac{\pi t}{12}\right)T(t)=15−3cos(12πt)
T(t)=10+e0.2tT(t) = 10 + e^{0.2t}T(t)=10+e0.2t
471 exam-style questions on Edexcel A Level Maths Functions and Graphs, 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. Each one has a worked solution and a mark scheme showing where the marks go.