# Change just the regular math font in document

I have the following document and wish to replace only the regular (not italic) math font with Liberation Serif to match the rest of the document.

Is this possible?

\documentclass[12pt]{article}
\usepackage{fourier}
\usepackage[T1]{fontenc}
\usepackage[no-math]{fontspec}
\setmainfont{Liberation Serif}
\begin{document}

The normal text set in Liberation Serif and maths \textbf{also,} instead of Adobe Utopia as intended
$v_x(t) = \lim\limits_{\Delta t \rightarrow 0} \frac{\Delta x}{\Delta t} = \frac{\mathrm{d}x}{\mathrm{d}t}$

\end{document}

• Several iitems: (a) fourier package sets the base font to Adobe Utopia and redefines the maths encodings (documentation, p1); (b) fontenc is not needed when using fontspec; (c) use \setmathrm{Liberation Serif} to set the mathrm font. – Cicada Sep 22 at 10:24
• Oh, and (d) remove the no-math option to fontspec so that it can update the maths fonts. – Cicada Sep 22 at 10:36