## Monday, November 3, 2008

### \bar vs. \overline

Another quick post, this time about math. In particular about the \bar option. As many Latex users are aware, the \bar option is used to put a line over a letter/number in math mode, usually representing a mean. The problem with this method is that it puts a fixed-width bar over the letter (I think it's an underscore character '_') instead of covering the width of the letter(s).

This can be easily overcome with the overline option.

overline: \overline
usage: \overline{test}
Explanation: The overline option should be used instead of bar option.

The following code demonstrates the difference

\documentclass[12pt]{beamer}
\mode{
}
\begin{document}
\begin{frame}[plain]
\begin{align*}
Z& = \frac{\bar{BMI}-\mu}{\sqrt{\frac{\sigma^2}{N}}} \\
& = \frac{\bar{BMI}-\mu}{SE(\bar{BMI})} \\
\end{align*}
\begin{exampleblock}{RIGHT}
\begin{align*}

Z& = \frac{\overline{BMI}-\mu}{\sqrt{\frac{\sigma^2}{N}}} \\
& = \frac{\overline{BMI}-\mu}{SE(\overline{BMI})} \\
\end{align*}
\end{exampleblock}
\end{frame}
\end{document}

Which produces the following slide

1. Thanks, this was exactly what I was looking for. Keep it up!

2. It helps a lot...

3. Thanks so much.

4. This comment has been removed by a blog administrator.

5. Thanks so much. I really needed this for my thesis.

6. Thanks! Just what the doctor ordered.

7. Many Thanks!

8. Thank you!! My thesis was looking weird until I found this.

9. Thank you, though if you have an index to the letter than the overline, there is a white space between the letter and its index and it looks horrible.

\documentclass[12pt]{beamer}
\begin{document}

$\overline{V}_\textrm{p}$ instead of $\bar{V}_\textrm{p}$

\end{document}

Does anyone knows how to avoid the space between the V and p?

Thanks

10. You can put whatever you want in the argument to the overline command, so to put the overline above a number and its subscript, you do:

$\overline{V_\textrm{p}}$

11. You can also eliminate the space without having the overline cover both the symbol and its subscript by inserting a negative space (\!) between them:

$\overline{V}\!_\textrm{p}$

1. Thank you Kbolino, that's exactly what I was looking for.

12. That made my notes look nicer, and also lead me to try underline, which is what I wanted elsewhere. Thanks!

13. Thanks, nice tip!

14. THANK YOU! :)

15. Thank you for helping me write my paper!

16. Thanks! It saved the beauty of my thesis!