Take the 2-minute tour ×
TeX - LaTeX Stack Exchange is a question and answer site for users of TeX, LaTeX, ConTeXt, and related typesetting systems. It's 100% free, no registration required.

I know the spacing produced by the following two approaches is slightly different. So my question is which one should I choose? Is it about personal preference?

With 3 consecutive equation environments

spacing example

With a single gather environment

gather example

Code

\documentclass[preview,multi,border=12pt]{standalone}
\usepackage{amsmath}


\begin{document}

\begin{preview}
The following equations are too simple,
\begin{equation}
v_t=v_0+at
\end{equation}
\begin{equation}
s=v_0t+\tfrac{1}{2}at^2
\end{equation}
\begin{equation}
v_t^2=v_0^2+2as
\end{equation}
where $a$ is the acceleration.
\end{preview}


\begin{preview}
The following equations are too simple,
\begin{gather}
v_t=v_0+at\\
s=v_0t+\tfrac{1}{2}at^2\\
v_t^2=v_0^2+2as
\end{gather}
where $a$ is the acceleration.
\end{preview}

\end{document}
share|improve this question
1  
Simply looking at the result shows that the separate equation environments are wrong. Can you see the different interline spacing? –  egreg Nov 5 '12 at 12:40
    
@egreg : interline spacing between the equations? –  I am who I say I am Nov 5 '12 at 12:42
    
personally I would prefer alignat which gives same spacing as gather. –  mythealias Nov 5 '12 at 12:43
1  
Look between equation (1) and (2), and between (2) and (3). No way this can be "personal preference": it's wrong spacing. –  egreg Nov 5 '12 at 12:43
    
@egreg: It should be regarded as unbalanced spacing (rather than wrong spacing) I think. –  I am who I say I am Nov 5 '12 at 12:45
add comment

2 Answers

up vote 6 down vote accepted

You definitely shouldn't do it with 3 consecutive equations. As you said yourself, the spacing is unbalanced. Here's why: The line before the first equation is "long", so TeX uses \abovedisplayskip above it, and \belowdisplayskip below. The other two equation don't have text before them, or you could say the text before the equations is "short". Thus, TeX uses \abovedisplayshortskip and \belowdisplayshortskip. As a result, you have

  • \belowdisplayskip + \abovedisplayshortskip between the 1st and the 2nd equation, and
  • \belowdisplayshortskip + \abovedisplayshortskip between the 2nd and the 3rd equation.

I'd use align (and not gather) to obtain horizontal alignment and balanced vertical spacing:

\begin{align}
  v_t &= v_0 + at \\
    s &= v_0t + \tfrac{1}{2} at^2 \\
v_t^2 &= v_0^2 + 2as
\end{align}
share|improve this answer
    
What convention do we usually adopt to decide whether or not we need to use gather instead of align for consecutive equations? I am confused to make such a decision. I know it is about horizontal alignment for sure. –  I am who I say I am Nov 5 '12 at 13:06
    
If you have "natural" points for horizontal alignment, then use align. An 0 or \le sign is such a "natural" point. –  Hendrik Vogt Nov 5 '12 at 13:30
add comment

The line

s=v_0t+\tfrac{1}{2}at^2

produces a fraction which here does not give you a higher line. If you used a \frac{}{} instead, it might happen that one line will be higher than the others (if they are wo fractions), which is also unnatural. Then it helps to put \phantom{\frac{1}{2}} on the end of the other lines (after the dot or comma sign). At least then, even with consecutive equations, which I don't recommend, the spacing would be balanced.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.