%% formulation
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\begin{document}
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\begin{align*}
\min_{u(t)} \quad & \frac{1}{2} \int_{0}^{t_f} x_1^2 \mathrm{d}t \\
\text{subject to:} \quad & \dot{\bm{x}} = \begin{bmatrix}0 & 1 \\ 0 & 0 \end{bmatrix} \bm{x} + \begin{bmatrix} 1 \\ -1 \end{bmatrix} u \\
& \bm{x}(0) = (\alpha,\beta) \\
& \bm{x}(t_f) = (0,0) \\
& |u(t)| \leq \gamma
\end{align*}
}}
\end{document}

%% solution