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