title: LaTeX/Beamer,  column environment.  Horizontal alignment of overlays
body: <p>I am trying to prepare a presentation using <code>beamer</code>.  I want to have two columns that walkthrough some algebraic manipulations.  On the left an explanation of the steps taken, on the right the results.</p>
  
  <pre><code>\documentclass{beamer}
  \begin{document}
  
     \begin{frame}[t]
     Not in a column
     \begin{columns}[t]
        \begin{column}{0.5\textwidth}
              \only&lt;2-&gt;{Some text}
  
              \only&lt;3-&gt;{
                        Lorem ipsum dolor sit amet, consectetur adipiscing elit.
                       }
        \end{column}
        \begin{column}{0.5\textwidth}
           \only&lt;2-&gt;
           {
           \begin{equation}
              E = mc^2
           \end{equation}
           }
  
           \only&lt;3-&gt;
           {
           \begin{equation}
              F = ma
           \end{equation}
           }
        \end{column}
     \end{columns}
     \end{frame}
  \end{document}
  </code></pre>
  
  <p>And here's some LaTeX which does that (with junk words and equations).  When this is compiled the text and maths are not aligned with each other.  I wouldn't really expect them to be either as LaTeX will position the text in each column individually, not caring about the other frames.</p>
  
  <p>Does anyone have any ideas on how to achieve the result I am after.  I'm not committed to the columns at all, but I am committed to the equation numbers.</p>