Bold, Upright and Beautiful epsilon

greekmath-mode

I was searching for upright, bold, and beautiful epsilon (or other) in math mode as shown here, but can't find it. I can do the right hand side of equation using \symbf but when used it with epsilon, it didn't work.
How do I get that?

Bold epsilon

Best Answer

You also can use a font which has upright greek letters (‘French style’) such as fourier. Here is a code, with some improvements as to the spacing:

\documentclass{article}
\usepackage{mathtools} 
\usepackage[upright]{fourier}

\begin{document}

\[ \underbrace{\overline{\boldsymbol{\varepsilon}}_k}_{\mathclap{\substack{\text{constant}\\ \text{in } \Omega^s_k}}} = \frac{1}{V^s_k}\int_{\Omega^s_k}\mathbf{L}_d \mathbf{u}^h(\mathbf{x})\,\mathrm{d}\Omega \]%

\end{document} 

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