% https://www.latex4technics.com/

% formulation
\documentclass{article}
\usepackage{amsmath}
\usepackage{bm}
\usepackage{graphicx}
\usepackage{geometry}
\geometry{top=0in, bottom=0in, left=0in, right=0in, paperheight=100in, paperwidth=100in}
\thispagestyle{empty}
\begin{document}
\scalebox{2}{\parbox{0.1\textwidth}{%
\begin{align*}
\min_{u_1(t)} \quad & -p_5\xi_1(t_f) + p_4 \int_{t_0}^{t_f} u_1 dt \\
\text{subject to:} \quad & \dot{\bm{\xi}} = \begin{bmatrix}
p_1 d_1(t) \xi_2(t) \\ p_2[d_2(t) - \xi_2(t)] + p_3u_1(t)
\end{bmatrix} \\
& \bm{\xi}(0) = \bm{\xi}_0 \\
& 0 \leq u_1(t) \leq u_{\max}
\end{align*}
}}
\end{document}

% solution