Why doesn't \mathbf{} make Greek letters bold in LaTeX?

[Chestermiller]

How do I make Greek letters boldface in LaTeX? When I try \mathbf{}, I just get the regular non-bold Greek letter.

 

[andrewkirk]

If you are working in a full LaTeX environment, try \boldmath. to switch on bolding all math chars including Greek letters then \unboldmath to turn it off. Both commands need to be outside the math environment.

In a full LaTeX environment, the following:

$\beta$\boldmath$\beta$\unboldmath$\beta$

comes across as three betas, normal, then bold, then normal.

It doesn't work in MathJax (what PF uses), as that is not full LaTeX, and the commands are issued outside of math environment. Below is what happens with a simple attempt:

##\beta##\boldmath##\beta##\unboldmath##\beta##

gives

$\beta$\boldmath$\beta$\unboldmath$\beta$

Fortunately, PF MathJax appears to have the LaTeX package amsbsy loaded by default, so you can use its \boldsymbol command. The following code

##\beta\boldsymbol{\beta}\beta##

gives

$\beta\boldsymbol{\beta}\beta$

 

[Chestermiller]

If you are working in a full LaTeX environment, try \boldmath. to switch on bolding all math chars including Greek letters then \unboldmath to turn it off. Both commands need to be outside the math environment.

In a full LaTeX environment, the following:

$\beta$\boldmath$\beta$\unboldmath$\beta$

comes across as three betas, normal, then bold, then normal.

It doesn't work in MathJax (what PF uses), as that is not full LaTeX, and the commands are issued outside of math environment. Below is what happens with a simple attempt:

##\beta##\boldmath##\beta##\unboldmath##\beta##

gives

$\beta$\boldmath$\beta$\unboldmath$\beta$

Fortunately, PF MathJax appears to have the LaTeX package amsbsy loaded by default, so you can use its \boldsymbol command. The following code

##\beta\boldsymbol{\beta}\beta##

gives

$\beta\boldsymbol{\beta}\beta$

Excellent! Thank you so much.

 

[Chestermiller]

$$\boldsymbol{\sigma}=-p\mathbf{I}+2\eta \mathbf{E}$$