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\documentclass[12pt]{article}
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\usepackage{amsmath}
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\begin{document}
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\begin{align*}
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\mathbf r^{n+1}_{ij} \cdot \mathbf r^{n+1}_{ij} &= d^2_{ij} \quad \text{and} \\
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\mathbf v^{n+1}_{ij} \cdot \mathbf r^{n+1}_{ij} &= 0, \label{eq:velcon}
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\end{align*}
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\end{document}
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