\documentclass{standalone}
\standaloneconfig{margin=2mm}
\usepackage{tikz}
\usepackage{pgfplots}
\pgfplotsset{compat=1.18}

\begin{document}

\begin{tikzpicture}[scale=1.5]
    \begin{axis}[axis lines=center,
	xlabel={$x$},
	ylabel={$y$},
	xtick=\empty,ytick=\empty,
	xmin=-0.2,xmax=4.2,
	ymin=-0.2,ymax=3,
	unbounded coords=jump,
	samples=200]
	\draw[scale=1,domain=0.2:3.2,smooth,variable=\x,blue] plot ({\x},{cos(\x r)+1.5});
	\filldraw[red] (pi/2,1.5) circle (1pt) node[above right] {point d'inflexion};
	\draw[->gt;] (pi/2,1.5) -- (pi/2+0.4,1);
	\draw[->gt;] (pi/2,1.5) -- (pi/2-0.4,2);
     \end{axis}
\end{tikzpicture}

\end{document}