Writing bold mathematical symbols

There are several ways to get bold mathematical symbols. LaTeX directly provides a classic method. Take a look at this code:

\boldmath $y=f(x)$\unboldmath

It works like this:

1. In text mode, we switch to bold math alphabets.
2. We enter math mode, in which bold symbols are always chosen, if available.
3. We leave math mode.
4. While in text mode, we switch the math alphabet back to normal – non-bold.

However, this makes all symbols a formula bold. This kind of emphasis is somewhat rare today, as it destroys the uniform grayness of the text from a typographer’s point of view.

A more common requirement is to get bold versions of certain symbols. For example, bold symbols are often used for vectors and number systems.

In this recipe, we will take the most recommendable approach to get bold symbols.

How to do it...

We will use the bm package, as follows:

1. Load the bm package in your preamble. Do this...