How to write the letter θ as bold and not italic?
I have tried the following but it gives me the θ as italics and not bold:
\textbf{$\theta$}
[Tex/LaTex] How to write a greek letter as bold and not italic?
boldgreekmath-mode
Related Solutions
This has nothing to do with the documentclass, but with font selection. \it selects non-bold italics, and \bf selects non-italic bold. You should use
\textbf{\textit{vs}}
instead. See also this question.
You could use the bm package and its command \bm. One of the very nice things about this package is that \bm works equally well on letters and symbols; thus, one doesn't have to remember to use \mathbf on letters and \boldsymbol on symbols. Another nice aspect -- especially useful for your setup -- is that you get bold-italic rather than bold-upright output.
\documentclass{article}
\usepackage{bm}
\begin{document}
\begin{equation}
\bm{F} = k\bm{x}
\end{equation}
\end{document}
Best Answer
Instead of
\textbfuse\boldsymbol(load the amsmath package to get it) to get it bold, put everything in math mode, and to get it upright use the upgreek package and\upthetainstead oftheta:If you do not need it just for one theta, also see at Bold math: Automatic choice between \mathbf and \boldsymbol for Latin and Greek symbols?