Centering the “main” part of an equation

centerequationsmath-mode

As per the title, I want to center the "main" part of a display math equation and have the rest be positioned offset to it.

What I mean is, considering the following document:

\documentclass{article}

\usepackage{mathtools}

\begin{document}
Here is my favorite equation:
\[ a = b + c \;\text{where}\; a = 5, b = 3, c = 2 \]
\end{document}

The equation is centered considering all of its content, which is expected behavior.

What I would want is something akiing to WithArrows's DispWithArrows: Just the "a = b + c" at the center of the page, with the "where" bit to the right of it.

Arrays, align, alignat et ceter aobviously do not work for what I'm saying. one idea I've thought of is having a phantom of the "annotation" on the other side in an array with rcl columns, but that's very dirty.

Thank you all in advance for any help.

Best Answer

Smash it! Looks terrible, but I think it's what you asked for (actually it might look better with a wider space after the equation; try \quad or \qquad in place of \;).

\documentclass{article}
\usepackage{mathtools}
\usepackage{lipsum}
\begin{document}
Here is my favorite equation:
\[ a = b + c \mathrlap{\;\text{where}\; a = 5, b = 3, c = 2} \]
\lipsum[1]
\end{document}

Horizontally smashing places objects inside boxes of zero width, so they don't affect centering etc. You can find details of \mathrlap in the mathtools package documentation.

Code

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\[
%
l_{12} =  \frac {m_{c} c_{c} \frac {dT_{c}}{dt} + m_{s} c_{s} \frac {dT_{s}}{dt}}{m_{s}} \Delta t 
%
\]

\[
l_{12} =  \frac {m_{c} c_{c} \frac {dT_{c}}{dt} + m_{s} c_{s} \frac {dT_{s}}{dt}}{m_{s}} \Delta t 
\]

\begin{equation}
l_{12} =  \frac {m_{c} c_{c} \frac {dT_{c}}{dt} + m_{s} c_{s} \frac {dT_{s}}{dt}}{m_{s}} \Delta t 
\end{equation}

\begin{equation*}
l_{12} =  \frac {m_{c} c_{c} \frac {dT_{c}}{dt} + m_{s} c_{s} \frac {dT_{s}}{dt}}{m_{s}} \Delta t 
\end{equation*}
\end{document}

Output

[Tex/LaTex] Increasing vertical space after equation in paragraph with short previous line

You seem to want that \belowdisplayshortskip is set equal to \belowdisplayskip; the former is used if the line above the display is “short”. The parameters are set in \normalsize (and also in \small and \footnotesize). Just append the appropriate declaration.

\documentclass{article}
\usepackage{etoolbox}
\appto\normalsize{\belowdisplayshortskip=\belowdisplayskip}
% the following two are not strictly necessary
\appto\small{\belowdisplayshortskip=\belowdisplayskip}
\appto\footnotesize{\belowdisplayshortskip=\belowdisplayskip}

\begin{document}

The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the.
\begin{equation}
  \frac{a}{b}
\end{equation}
The paragraph continues here.
The paragraph continues here.
The paragraph continues here.

The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps.
\begin{equation}
  \frac{a}{b}
\end{equation}
The paragraph continues here.
The paragraph continues here.
The paragraph continues here.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the lazy dog.
The quick brown fox jumps over the.

\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Centering equation on a line

Code

Output

[Tex/LaTex] Increasing vertical space after equation in paragraph with short previous line

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