\beginequation g(x) = \sqrtx \labeleq:root \endequation
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autonum is often preferred over mathtools ’ showonlyrefs because autonum works with more environments and handles \label placement more robustly. \documentclassarticle \usepackageamsmath \usepackage[colorlinks]hyperref \usepackagecleveref \usepackageautonum \begindocument autonum.info
% This equation will be numbered because it is referenced below \beginequation E = mc^2 \labeleq:einstein \endequation
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As Einstein said, see \eqrefeq:einstein.
\sectionTest
% This equation will NOT be numbered (no reference) \beginequation a^2 + b^2 = c^2 \endequation