# Math font family for Merriweather (black) font family

I want to use a strong font in my text, like \usepackage[black]{merriweather}, but it also has a lot of equations. So, is there any "strong" math font I could use?

\documentclass[11pt,a4paper]{report}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage[T1]{fontenc}
\usepackage[black]{merriweather}
\usepackage{lipsum}
\begin{document}

\chapter{Introduction}
\lipsum[2] $x=4$.

\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}

\end{document}


I can not use XeTeX or LuaTex.

• Have you looked here? – cfr May 31 '16 at 21:52
• Your example show the effect of the black option in the section headings but not in the text, is that correct? So what should the maths match? Presumably you want something with (1) a bold series (2) a heavier bold series? Or ...? – cfr May 31 '16 at 21:54
• @cfr In fact, I completely forgot that option on the Font Catalog .Thanks – Costa PR May 31 '16 at 21:56
• Really, I think for TeX, it doesn't make sense to pick text fonts and then try to match in maths. You need to make your font selection for both text and maths or, failing that, pick your maths first. – cfr May 31 '16 at 22:00
• I found \usepackage{fouriernc} on the Font Catalog. But how I set it just for math? – Costa PR May 31 '16 at 22:00

If you want to use fouriernc for maths but Merriweather for text, just load fouriernc before merriweather:

\documentclass[11pt,a4paper]{report}
\usepackage[utf8]{inputenc}
\usepackage[english]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage[T1]{fontenc}
\usepackage{fouriernc}
\usepackage[black]{merriweather}
\usepackage{lipsum}
\begin{document}

\chapter{Introduction}
\lipsum[2] $x=4$.

\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}

\end{document}


# EDIT

It is very difficult to scale the fonts for maths straightforwardly, but, as you pointed out, it is possible to alter the point sizes LaTeX uses for maths using code from Stefan Kottwitz's answer.

For example, to use the settings which are default for 12pt text in an 11pt document:

\documentclass[11pt,a4paper]{report}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{amsmath,amssymb}
\usepackage{fouriernc}
\usepackage[black]{merriweather}
\usepackage{lipsum}
\makeatletter
\DeclareMathSizes{\@xipt}{\@xiipt}{8}{6}% modified from fontmath.ltx
\makeatother
\begin{document}
\chapter{Introduction}
\lipsum[2] $x=4$.

\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}

$\int_0^\infty \frac{\sum_{n=-\infty}^{\infty}\frac{1}{n! + \dots 1}}{\prod_{k=i^{j^n}} \exp^k - \pi\delta }$

\end{document}


Note that, unlike font scaling, this must be done for every fontsize context in which you will use mathematics.

To illustrate, suppose that we'd set maths to be huge:

\DeclareMathSizes{\@xipt}{\@xxvpt}{\@xxpt}{\@xviipt}


(These sizes correspond to the largest text size LaTeX uses by default.)

Now suppose that we typeset the following

\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}

\small
\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}


Normally, we'd expect the second to be slightly smaller than the first. For example, with the default settings

However, with our enormous maths we will get the following mismatch

This is because \small alters the current text size and LaTeX chooses the sizes for maths according to the current text size. Because we didn't alter the sizes declared for \small, the default, much, much smaller settings are used.

Similarly, \large will have somewhat counterintuitive effects

\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}

\large
\begin{displaymath}
\Delta G^{\circ}= -R\,T\ln \dfrac{[S_1][S_2]}{[S_1S_2]}.
\end{displaymath}


That is, \large makes text bigger and maths smaller.

To avoid this, it would be best to redefine all the standard sizes LaTeX uses proportionately to avoid ending up with subtle inconsistencies in the size of maths.

• I have found a solution to Math size: (tex.stackexchange.com/questions/5148/…) \DeclareMathSizes{10.95}{x}{y}{z} – Costa PR May 31 '16 at 22:52
• @cfr I really didn't know that. Could you possible add if there are any sideeffects to this, and why it only effects math? – Runar May 31 '16 at 22:53
• The first entry must be the font size of the document (11 pt= 10.95). Also, the first option of \documentclass must be the size too. – Costa PR May 31 '16 at 22:57
• @runartrollet Please see edit. It only affects maths because LaTeX only uses maths font sizes in maths mode. I realise that sounds circular and it is: it is just the way LaTeX defines and uses these settings. – cfr May 31 '16 at 23:54
• @CostaPR Please see edit. Ideally, you should do this for all standard sizes. Certainly, you may wish to do it for more than 11pt in an 11pt document. – cfr May 31 '16 at 23:55