math-modepdftex
I would like to have a closing double quote in a mathematical expression in LaTeX. I found this answer which appears to explain how, so I tried the following:
\documentclass{article}
\begin{document}
$C = `` \textrm{dad} ''$
\end{document}
Unfortunately in my case this is the result:
As you can see the closing double quote is not correct. How can I get proper closing double quotes for my math expressions in LaTeX?
These option clashes happen when a package is requested to be loaded on two different positions, like by you and inside another package, but with different options. The package is loaded by the first \usepackage (or its twin \RequirePackage); it isn't loaded again when it is requested again. It simply can't be loaded a second time. Therefore the new options can be activated and previous options might conflict with the second usage. So LaTeX creates an error to report this issue to you.
The way to fix this is to declare the options beforehand using \PassOptionsToPackage{<options>}{<package>}. Then they are used wherever the package is loaded.
\documentclass{article}
\usepackage{ifpdf}
\ifpdf
\PassOptionsToPackage{pdftex,usenames,dvipsnames}{color}
\usepackage[T1]{fontenc}
\usepackage{libertine} % most likely loads 'color' itself
%\usepackage{lmodern} % doesn't load 'color'
\usepackage{color}
\usepackage[pdftex]{graphicx}
\else
%\bye
\fi
\begin{document}
Hello, world!
\end{document}
I can't test it by myself, because I don't have the libertine package installed.
I don't think you need to set pdftex manually. Normally packages do a good job recognizing the driver by themselves. Also you might want to use the extended xcolor package instead of color.
You can simply remove the option math when loading mathspec.
MWE
\documentclass[11pt]{article}
\usepackage{mathspec}
\setprimaryfont{Linux Libertine O}
\begin{document}
1 $1$ $\mathrm{1}$ $\text{1}$
\end{document}
Output
Loading mathspec with the math option forces mathspec to load fontspec without the no-math option.
And the fontspec manual states:
If you find that
fontspecis incorrectly changing the maths font when it should be leaving well enough alone, apply the[no-math]package option to manually suppress its maths font.
Best Answer
Using CMR font, you can get the opening and closing double quotation mark symbol by using the keyboard character itself,
Definitely the same will not work for all fonts, hence should use as per standard structure, i.e.,
$C = \text{``dad''}$