In LaTeX, there are multiple ways to write bold text, each serving different purposes depending on the context.
Whether you’re working with normal text, mathematical equations, or section titles, LaTeX provides several commands to achieve bold formatting.
textbf command
This is the most commonly used and straightforward method to bolden text in LaTeX. When you want to bold specific words or phrases in normal text, use the \textbf{...} command.
\textbf{Hello LaTeX}
bfseries command
The \bfseries command is another way to bolden text, but it applies to all content within its scope. Unlike \textbf{...}, it does not require enclosing the text in curly brackets unless you want to limit its effect.
{ \bfseries Hello LaTeX}
Since \bfseries is an environment-based approach, everything within the curly braces {} turns bold.
Bold mathematical variables
When working with mathematical equations, \textbf{...} will not work inside math environments. Instead, use \mathbf{...} to bold mathematical variables.
\[ \mathbf{F} = m \mathbf{a} \]
\begin*{equation}
\mathbf{r}= \mathbf{v}t
\end*{equation}
This method is particularly useful in physics and engineering, where vector quantities are often represented in bold.
Bold symbols and greek letters
The \mathbf{...} command can only bold letters, but if you need to bold Greek letters or mathematical symbols, use \boldsymbol{...} instead.
\[\boldsymbol{\alpha} + \boldsymbol{\beta} = 2\alpha\beta \]
Better bold formatting in math
Another powerful alternative for boldening mathematical symbols and Greek letters is the \bm{...} command from the bm package. It works better in some cases compared to \boldsymbol{...}.
\usepackage{bm}
...
\[ \bm{\alpha} + \bm{\beta} = \bm{\gamma} \]
Using \bm{...} provides a more reliable way to bold symbols, making it a preferred choice in complex equations.
