Creating bold and non-italic equations

Question

I am trying to write an equation in bold and non italic but I can't get it to work because I also want to write a D with two dots over it. Here is my code:

\begin{equation}
\text{\boldsymbol{{M} \ddot{D}} + KD = F}. 
\end{equation}

Thank you!

What do you mean by non cursive? Do you want to write all your math in non-italic? If so, you could find a way to do that by following this question and its answers. — SebGlav, Jul 25 '21 at 09:37
I have multiply equations but this is the only equation that I want non-italic. — user241377, Jul 25 '21 at 09:42
Try \begin{equation} \mathbf{M \ddot{D}} + KD = F. \end{equation} — Zarko, Jul 25 '21 at 09:44

score 2 · Answer 1 · answered Jul 25 '21 at 22:17

Let me spell out @egreg and my comments:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
@egreg proposition:
\begin{equation}
\mathbf{M}\ddot{\mathbf{D}} + KD = F. 
\end{equation}
My proposition:
\begin{equation} 
\mathbf{M \ddot{D}} + KD = F. 
\end{equation}
\end{document}

score 1 · Answer 2 · answered Jul 26 '21 at 09:32

First of all, there should be no \text: you want a math formula.

If you use \boldsymbol, you get bold (math) italic. If you want bold (math) upright, the command is \mathbf.

Also, each letter should be specified with a distinct call of \mathbf and the double dot (second derivative in Newton notation) should not be bold.

Hence

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
\mathbf{M} \ddot{\mathbf{D}} + KD = F
\end{equation}
\end{document}

The formula is not at all clear, though, but you know better.

Creating bold and non-italic equations

2 Answers2