How to get \bm{} to work in an R markdown (to HTML) file?

Question

My R Markdown (.Rmd) file looks like this:

---
title: Foo
author: Marius Hofert
header-includes:
    - \\usepackage{bm}
output:
    pdf_document
vignette: >
          


        

Answer 1

Another solution is to use the child chunk argument. The downside, which is kind of major, is that it will only work for math surrounded by $ $ or $$ $$. It won't work in the equation environment. The upside is that you do not get your definitions "flashing" at the top of your html pages for a moment, which happens to me with the solution above.

demo.Rmd

---
title: Foo
output:
  pdf_document: default
  html_document: default
---

```{r child = 'defs.tex'}
```

My math definitions are in defs.tex.  Now I can use the defs in equations
but they need to be in math mode for html output.  This works for both
pdf and html:
$\AA^\top\BB$ and 
$$\AA^\top\BB$$

But using your new commands in the equation environment
only works for pdf output because pandoc will not expand the
definitions if the newcommands are not in $ $ or $$ $$.    

\begin{equation}
\AA^\top\BB
\end{equation}

---

defs.tex

\newcommand{\BB}{\mathbf{B}}
\newcommand{\CC}{\mathbf{C}}
\renewcommand{\AA}{\mathbf{A}}