In mathematics, a letter, say, g, can stand for a scalar, while a letter in bold, e.g., **g** stands for a vector.

Here is my question:

How can one turn the letter into bold in the math mode?

For example, how can I turn g here into bold?

```
$$-\nabla p+\mu\nabla^2u+g\delta(x-x_0)=0 $$
```

## Best Answer

Using the

`bm`

package. The`\mathbf`

command can only be used for non-italic symbols, instead the`amsmath`

package defines the`\boldsymbol`

command that can be used with every literal symbol or math operator. The`bm`

package redefines the`\boldsymbol`

command providing the`\bm`

command and is independent from`amsmath`

. So you can use: