Helvetica for Latin letters and a sans-serif font for Greek letters

Question

I'm trying to be a perfectionist and desperately trying to make things right:

1. All Latin symbols should use Helvetica
2. Greek letters should be at least sans-serif (Helvetica in an ideal world)

Here is how I tried to solve:

\documentclass{beamer}
\usepackage{helvet}
\usepackage[EULERGREEK]{sansmath}
\sansmath
\begin{document}
GR17 \alpha \beta \gamma \mu\
$GR17 \alpha \beta \gamma \mu$
\end{document}

If I try this:

\documentclass{beamer}
\usepackage{sansmathfonts}
\usepackage{helvet}
\begin{document}
GR17 \alpha \beta \gamma \mu\
$GR17 \alpha \beta \gamma \mu$
\end{document}

Do you have any ideas how to fix this?

UPD: so far I found only a complex solution here:

\documentclass{beamer}
\usepackage{helvet}
\DeclareSymbolFont{sfletters}{OML}{cmbrm}{m}{it}
\DeclareMathSymbol{\alpha}{\mathord}{sfletters}{"0B}
\DeclareMathSymbol{\beta}{\mathord}{sfletters}{"0C}
\DeclareMathSymbol{\gamma}{\mathord}{sfletters}{"0D}
\DeclareMathSymbol{\delta}{\mathord}{sfletters}{"0E}
\DeclareMathSymbol{\epsilon}{\mathord}{sfletters}{"0F}
\DeclareMathSymbol{\zeta}{\mathord}{sfletters}{"10}
\DeclareMathSymbol{\eta}{\mathord}{sfletters}{"11}
\DeclareMathSymbol{\theta}{\mathord}{sfletters}{"12}
\DeclareMathSymbol{\iota}{\mathord}{sfletters}{"13}
\DeclareMathSymbol{\kappa}{\mathord}{sfletters}{"14}
\DeclareMathSymbol{\lambda}{\mathord}{sfletters}{"15}
\DeclareMathSymbol{\mu}{\mathord}{sfletters}{"16}
\DeclareMathSymbol{\nu}{\mathord}{sfletters}{"17}
\DeclareMathSymbol{\xi}{\mathord}{sfletters}{"18}
\DeclareMathSymbol{\pi}{\mathord}{sfletters}{"19}
\DeclareMathSymbol{\rho}{\mathord}{sfletters}{"1A}
\DeclareMathSymbol{\sigma}{\mathord}{sfletters}{"1B}
\DeclareMathSymbol{\tau}{\mathord}{sfletters}{"1C}
\DeclareMathSymbol{\upsilon}{\mathord}{sfletters}{"1D}
\DeclareMathSymbol{\phi}{\mathord}{sfletters}{"1E}
\DeclareMathSymbol{\chi}{\mathord}{sfletters}{"1F}
\DeclareMathSymbol{\psi}{\mathord}{sfletters}{"20}
\DeclareMathSymbol{\omega}{\mathord}{sfletters}{"21}
\DeclareMathSymbol{\varepsilon}{\mathord}{sfletters}{"22}
\DeclareMathSymbol{\vartheta}{\mathord}{sfletters}{"23}
\DeclareMathSymbol{\varpi}{\mathord}{sfletters}{"24}
\DeclareMathSymbol{\varrho}{\mathord}{sfletters}{"25}
\DeclareMathSymbol{\varsigma}{\mathord}{sfletters}{"26}
\DeclareMathSymbol{\varphi}{\mathord}{sfletters}{"27}
\begin{document}
GRQ17\
$GRQ17 \alpha \beta \gamma \mu \Delta \delta \Sigma \Gamma \pi$\
\end{document}

Maybe not bold enough, but it is better than it was before. I wonder if somebody knows a more elegant solution to the problem.

Answer 1

In the Modern Toolchain

In LuaLaTeX or XeLaTeX, you can load a sans-serif math font with unicode-math. You can even load a font of your choice for Greek, with \setmathfont[range=....

One sans-serif math font is Fira Math, and the version of Helvetica that comes with TeX is TeX Gyre Heros.

\usepackage{unicode-math}
\defaultfontfeatures{ Scale=MatchLowercase, Ligatures=TeX }
\setmainfont{TeX Gyre Heros}[Scale=1.0]
\setmathfont{Fira Math}

To get actual Helvetica for \mathit, add \setmathfont[range=it/{Latin,latin,digits}]{TeX Gyre Heros Italic}. You can repeat this for upright, bold and bold italic if you need those too.

In the Legacy Toolchain

My personal recommendation is to use LuaLaTeX and unicode-math when you can, and PDFLaTeX when you have to. Some publishers in 2020 still require it. Here’s a solution for when you have to.

Load a sans-serif math package, such as newtxsf or sansmathfonts or arevmath, and tgheros as your sans-serif font, then renew \familydefault to make it the main font.

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc} % The default since 2018
\usepackage{tgheros}
\renewcommand*\familydefault{\sfdefault}
\usepackage{newtxsf}
\begin{document}
GRQ17\
$GRQ17 \alpha \beta \gamma \mu \Delta \delta \Sigma \Gamma \pi$\
\end{document}

To get Helvetica in math mode, for Latin letters, load mathastext. There does not happen to be a Type 1 version of Helvetica that supports Greek.

\documentclass{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc} % The default since 2018
\usepackage{tgheros}
\renewcommand*\familydefault{\sfdefault}
\usepackage{newtxsf}
\usepackage[italic]{mathastext}
\begin{document}
GRQ17\
$GRQ17 \alpha \beta \gamma \mu \Delta \delta \Sigma \Gamma \pi$\
\end{document}