Let $f:[0, \infty) \rightarrow[0,3]$ be a function defined by $\mathrm{f}(\mathrm{x})=\left\{\begin{array}{cc}\max \{\sin \mathrm{t}: 0 \leq \mathrm{t} \leq \mathrm{x}\}, & 0 \leq \mathrm{x} \leq \pi \\ 2+\cos \mathrm{x}, & \mathrm{x}>\pi\end{array}\right.$ Then which of the following is true ?