# What is the optimal way to align equations in BEAMER-class?

I have encountered many different environment for aligning equations: align, equation, alignat, gather, etc.

However, what is the optimal environment to use in a BEAMER-class? More specifically, what achieves: 1. Vertical alignment of different equations across the frames, i.e. same starting point on the page 2. Minimal white space below and above equations to enhance the audience's experience. 3. Minimal distance between equation number (left-side) and the equations.

Current code in the preamble:

\documentclass[leqno]{beamer}

\usetheme{CambridgeUS}
\usecolortheme{seahorse}
\useinnertheme{rectangles}
\usefonttheme{professionalfonts}
\setbeamercovered{dynamic}

\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsthm}
\usepackage[utf8]{inputenc}

\setlength{\mathindent}{0pt}
\AtBeginDocument{%
\abovedisplayskip=8pt
\abovedisplayshortskip=0pt
\belowdisplayskip=0pt
\belowdisplayshortskip=0pt
}



Thanks for any tips!

• about your point 1: With your settings, the content is vertically centred, so the starting point will depend on the amount of content. If you want the same starting points, you could try \documentclass[leqno,t]{beamer} Aug 3, 2018 at 11:18
• Personally I disagree with your point 2. A reasonable amount of white space will make it easier to read your equations, both too much and too less are bad. Aug 3, 2018 at 11:20
• About point 3: This probably depends very much on the topic, but I usually don't think that equations numbers are a good idea in a presentation Aug 3, 2018 at 11:21
• You wrote, "I have encountered many different environment[s] for aligning equations: align, equation, ..." IMNSHO, it seems weird to claim that equation environments can be used to align equations, unless the equation environments are combined with split or aligned environments (neither of which you mention). Regarding your first objective: Why on earth would, or should, anyone in the audience of your presentation care about the alignment of equations across frames? If you really expect them to notice (let alone care about) such details, you're in for serious disappointment.
– Mico
Aug 3, 2018 at 11:36
• OTOH, I assumed you meant horizontal alignment. To achieve vertical alignment (one equation per frame} you would use \parbox or minipage with the same height above and below the alignment point (centered). Aug 3, 2018 at 16:04

You can use \mathmakebox to align expressions in any equation environment, in any frame. As far as I know, only flalign will let you align to the left side, though.

\documentclass[leqno]{beamer}

\usetheme{CambridgeUS}
\usecolortheme{seahorse}
\useinnertheme{rectangles}
\usefonttheme{professionalfonts}
\setbeamercovered{dynamic}

\usepackage{mathtools}
\usepackage{amsthm}
%\usepackage[utf8]{inputenc}% not with my editor

%\setlength{\mathindent}{0pt}
\AtBeginDocument{%
\abovedisplayskip=8pt
\abovedisplayshortskip=0pt
\belowdisplayskip=0pt
\belowdisplayshortskip=0pt
}

\newlength{\mylength}

\begin{document}
\settowidth{\mylength}{$\displaystyle \left. \frac{\partial J}{\partial x}\right|_{x\in S}$}
\begin{frame}
Some text here.
\begin{flalign}
\mathmakebox[\mylength][r]{S}&=\lbrace x>0 \rbrace &&
\end{flalign}
some more text
\begin{flalign}
\left. \frac{\partial J}{\partial x}\right|_{x\in S} &=F(x) &&
\end{flalign}
and finishing with text.
\end{frame}
\begin{frame}
Continued alignment on next frame.
\begin{flalign}
\mathmakebox[\mylength][r]{S}&=\lbrace x>0 \rbrace &&
\end{flalign}
\end{frame}
\end{document}

• Thanks for the response! Is there an alternative to 'fleqno' global-setting. 'fleqno' achieves the left-alignment, but it does not align with 'leqno'.
– Sean
Aug 4, 2018 at 9:58