I want to use minipage to reach this result:
But my code:
\begin{minipage}[t]{0.5\textwidth}
Solve the problem (\ref{pdeb09_002}) for the function
$$
\varphi(x)=x^2 \text { on }[-\pi, \pi]
$$
that is extended $2 \pi$-periodically to $\mathbb{R}$.\\
Here is the graph of this function:
\end{minipage}
\begin{minipage}{0.38\textwidth}
\includegraphics[width=\textwidth]{Figures/001_b9.pdf}
\end{minipage}
\begin{minipage}[t]{...}
\usepackage[export]{adjustbox}
to your preamble and then use\includegraphics[...,valign=t]{<image>}
.