Math & Science ⇒ Size Problem with Root Sign

[Cham]

I'm having a size problem with the square root. See the following compilable code :

Code: Select all

\documentclass[12pt,letterpaper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[french]{babel}
\usepackage{lmodern} % interaction between these two packages ?
\usepackage{amsmath} %

\begin{document}
	\begin{equation}
		\sqrt{\varphi^2 - \vartheta^2} = \sqrt{E^2 - B^2}.
	\end{equation}
\end{document}

The first square-root sign isn't right (too big). The second square-root sign is nice.

If I comment out the lmodern package, the first square-root sign turns fine. If I comment-out BOTH the lmodern and the amsmath packages, the first square-root sign turns ugly (the second square-root doesn't change). So I guess the amsmath package is what gives a nice output, while the lmodern package turns-off that feature.

How can I tell LaTeX to keep the nice amsmath output, while still using the lmodern package ?

Changing the packages loading order doesn't help here.

[Stefan Kottwitz]

Hi Cham,

I guess the descender of the \varphi is the cause. You could smash it to get a smaller square root, as a workaround:

Code: Select all

\sqrt{\smash{\varphi}^2 - \vartheta^2} = \sqrt{E^2 - B^2

Stefan

[localghost]

The "culprit" is definitely the lmodern font package. The design of the Greek phi provides a slightly different descender that seems to cause the automatic scaling of the root sign.

You can hide the sizes of the box (depth here) that contains the phi by the \smash command.

Code: Select all

\documentclass[12pt,letterpaper,french]{article}
\usepackage[T1]{fontenc}
\usepackage{selinput}
\SelectInputMappings{
  aacute={á},
  ccedilla={ç},
  Euro={€}
}
\usepackage{babel}
\usepackage{mathtools}   % loads »amsmath«
\usepackage{lmodern}

\begin{document}
  \begin{equation}
    \sqrt{\smash{\varphi}^2-\vartheta^2}=\sqrt{E^2-B^2}.
  \end{equation}
\end{document}

By the way, good example.


Thorsten

[Cham]

Aah ! Thanks guys, now it's perfectly clear.

I learn a new thing each day !

Case solved !