67

I would like to put in a code that automatically assigns a number to the equations in my documents preferably aligned on the right hand side.

How can I go about this?

\documentclass[a4paper,11pt]{article}
%\documentclass[a4paper,11pt]{scrartcl}
\usepackage{amsmath} 
\usepackage[utf8]{inputenc}

\begin{document}

$$\ddot{\underline{\mathbf{r}}} = \frac{d{^2}\underline{\mathbf{r}}}{dt^2}= 0$$. 
\end{document}
1
  • has this question really not been asked before?
    – Vivi
    Commented Oct 8, 2012 at 1:31

2 Answers 2

56

You can use display math environment such as equation:

enter image description here

Notes:

  • The d in dt should be upright as d is an operator, not a variable. Have defined a macro for that and corrected it below.

References:

Code:

\documentclass{article} 

\newcommand{\dd}[1]{\mathrm{d}#1}

\begin{document}

\begin{equation}
\ddot{\underline{\mathbf{r}}} = \frac{\dd{}{^2}\underline{\mathbf{r}}}{\dd{t}^2} = 0
\end{equation}
\end{document}
5
  • 3
    I think we don't need the trailing s in Voss's. Commented Oct 8, 2012 at 2:02
  • @ガベージコレクタ: Have corrected that. Commented Oct 8, 2012 at 3:15
  • 1
    “See Why is \[...\] prefereable to $$”; yeah, especially Harrold's and Hendrik's comments to the accepted answer.
    – morbusg
    Commented Oct 8, 2012 at 3:18
  • @morbusg: Thanks for pointing those comments out. Perhaps those should be added as an answer so that thy are not missed. But, then David Carlisle's answer about $$ not easily being re-definable might be a better reason. Commented Oct 8, 2012 at 3:22
  • 2
    @kissmyarmpit nothing wrong with a trailing s there. perfectly acceptable according to conventional grammar.
    – abcd
    Commented Oct 23, 2015 at 20:58
22

You can also use the align environment:

\documentclass[a4paper,11pt]{article}
%\documentclass[a4paper,11pt]{scrartcl}
\usepackage{amsmath} 
\usepackage[utf8]{inputenc}

\begin{document}
%Equations with numbering
\begin{align}
\ddot{\underline{\mathbf{r}}} &= \frac{d{^2}\underline{\mathbf{r}}}{dt^2}\\
                              &= 0
\end{align} 

%Equations with no numbering in specific line by using \nonumber
\begin{align}
\ddot{\underline{\mathbf{r}}} &= \frac{d{^2}\underline{\mathbf{r}}}{dt^2}\nonumber\\
                              &= 0
\end{align}

%Equations without numbering
\begin{align*}
\ddot{\underline{\mathbf{r}}} &= \frac{d{^2}\underline{\mathbf{r}}}{dt^2}\\
                              &= 0
\end{align*} 
\end{document}

enter image description here

5
  • That is not working for me.EDIT sorry I didn't notice those \\ after the equation.
    – Magpie
    Commented Oct 8, 2012 at 0:23
  • 1
    @Magpie Is everything working fine now?
    – azetina
    Commented Oct 8, 2012 at 0:29
  • Yes, I was just having a sloppy moment. Thanks for your help. I selected the other answer because it does what I want more precisely but I appreciate your solution too.
    – Magpie
    Commented Oct 8, 2012 at 0:35
  • 1
    How can I reference those lines then? Commented Sep 29, 2020 at 3:07
  • 2
    @MinhNghĩa label with the command \label{ } then reference with \ref{ }
    – azetina
    Commented Sep 29, 2020 at 3:30

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