Issues When Two Math Fonts Are Combined

Question

Hi everybody: I'm having issues with some symbols when writing using the sans serif font. More concretely: I load a font for math and text (mtpro lite in the example below) and also Fira Sans for sans serif. AFAIK Fira Sans has math support through the package newtxsf.

\documentclass[14pt, a4paper, reqno]{extarticle}
\usepackage[full]{textcomp}
\usepackage[T1]{fontenc}
\usepackage[lite]{mtpro2}
\usepackage[scale=0.85]{FiraSans}
\usepackage{newtxsf}
\renewcommand{\rmdefault}{ptm}

\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amstext}
\usepackage{amsthm}
\usepackage[all]{xy}

My question is: is there a way to get full math support in certain paragraph that I need to type in sans serif? For example get also Fira Sans with its math symbols when using \mathsf. I tried with and without newtxsf, tried with sansmath package, even tried without specifying Fira Sans as sans serif font. Some symbols are not showed correctly (in some cases integrals, greek letters, etc). Thank you.

Answer 1

If I understand what you’re asking correctly, what you want is to declare a math version. Here is an example that uses the modern toolchain, and compiles with either LuaLaTeX or XeLateX:

\documentclass{article}
\usepackage{unicode-math}

\defaultfontfeatures{Scale = MatchLowercase}
\setmainfont{TeX Gyre Termes}[Scale=1.0]
\setsansfont{Fira Go}
\setmathfont{TeX Gyre Termes Math}
\setmathfont[version=sans]{Fira Math}

\begin{document}
This paragraph uses a serif font. \( x = yz^2 \).

{\sffamily\mathversion{sans}
This paragraph uses a sans-serif font. \( x = yz^2 \).}
\end{document}

If you have to use legacy 8-bit fonts with PDFLaTeX, you can accomplish something similar with \DeclareMathVersion and \SetMathAlphabet, but you have to look up the different math symbol fonts from both packages you want to combine. See “LaTeX2e Font Selection.”