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\documentclass[12pt]{article}
\usepackage{amsmath}

\begin{document}

%\begin{equation}

%\begin{split}

 $\theta$(\textit{g}$_1$) * ($\theta$(\textit{g}$_2$))$^{-1}$  = $\theta$(\textit{g}$_1$) * $\theta$(\textit{g}$_2^{-1}$) \\
= $\theta$(\textit{g}$_1$ \textit{g}$_2^{-1}$) \\
= $\theta$(\textit{g}) $\in$ \textit{G}, where \textit{g} = \textit{g}$_1$ \textit{g}$_2^{-1}$
%\end{split} 

%\end{equation}

\end{document}
  1. I'm trying to align the equal signs but remove the comments gives a '}' missing error
  2. Is there a way to avoid all the '$' inside the equation?
campa
  • 31,130
Athena Widget
  • 653
  • 1
    welcome to tex.sx. the equation environment is all math, so putting $ signs in the individual lines of the equation is not only not needed, but causing trouble. also, there is no need to specify italic for single letters -- all letters are italic there. and for text, such as "where", you should enter that as \text{ where }; notice the spaces on either side of "where". these features are provided by amsmath; look at the examples in the user's guide: texdoc amsmath. – barbara beeton Feb 15 '17 at 14:27
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    See http://tex.stackexchange.com/questions/98397/enumerate-formulas/98401#98401 – Ethan Bolker Feb 15 '17 at 14:50
  • Thx!! That's what I needed. – Athena Widget Feb 15 '17 at 20:01

1 Answers1

2

Like this?

enter image description here

Code is simple:

\documentclass[12pt]{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}
\begin{split}
\theta (g_1)\cdot (\theta(g_2))^{-1}  
    & = \theta(g_1)\cdot \theta (g_2^{-1})    \\
    & = \theta(g_1\textit{g}_2^{-1})                   \\
    & = \theta(g) \in G, \text{ where } g = g_1 g_2^{-1}
\end{split}
\end{equation}

\end{document}
Zarko
  • 296,517
  • 1
    @AthenaWidget, yes, so called math environments are in LaTeX started with $, \(, \[, \begin{equation} (numbered), \begin{equation*} (not numbered). Beside this, there is a plenty others math environments (m,odes), determined by amsmath or other packages. I suggest you to read some introductory text about LaTeX, for example No so short introduction to LaTeX 2e and similar. Also is worth to read https://en.wikibooks.org/wiki/LaTeX/Mathematics. – Zarko Feb 15 '17 at 20:04
  • Thx!! I saw the comment above as well. I'm very new to this. – Athena Widget Feb 15 '17 at 20:07