How to put align two things between a long vertical bar?

Question

Basically what I want is something like this

###### | ######
###### | ######
###### | ######
###### | ######
###### | ######
###### | ######

where # represents a derivation for an equation or something. I also cannot figure out the vertical line option with just \vline[30pt].

Answer 1

Based on your comments it appears that you want to be able to use an align environment inside a tabular. If that is the case then you need to wrap the align within a \parbox:

Code:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{tabular}{l|l} 
left content & right content\\ 
left content & right content\\ 
\parbox{0.3\linewidth}{%
    \begin{align*} 
        E &= mc^2 \\ 
        F &=ma
    \end{align*}} & right content\\ 
left content & right content\\ 
\end{tabular}
\end{document}

Answer 2

You can indeed use tabular type of environments, alternatively, you can use the minipage environment which may give you more flexibility with what you want to achieve:

\documentclass[a4paper,12pt]{article}

\usepackage{lipsum}

\begin{document}
\begin{minipage}[t]{.4\linewidth}
\lipsum[1]
\end{minipage}
\hfill
\vline
\hfill
\begin{minipage}[t]{.4\linewidth}
\lipsum[2]
\begin{align*}
x^2 + y^2 &= 1\\ 
y &= \sqrt{1 - x^2}.
\end{align*}
\begin{align}
u &= \arctan x & dv &= 1 \, dx\\ 
du &= \frac{1}{1 + x^2} dx & v &= x.
\end{align}
\end{minipage}
\end{document}

This will give:

Answer 3

Here is a solution using the multicol package. You can make the line separating the columns visible by setting \columnseprule to something greater than 0pt. The advantage of this technique is that content can flow from one column to the next.

Code:

\documentclass[10pt]{article}

\usepackage[]{amsmath,amssymb}

\usepackage[]{multicol}
\setlength{\columnsep}{1cm} % space between columns
\setlength{\columnseprule}{1pt} % vertical line thickness

\usepackage[]{microtype}

\usepackage[]{lipsum} %<---used only to generate dummy text

\begin{document}
\begin{multicols}{2}

\lipsum[1]
%
\begin{align}
a^2+b^2&=c^2\\
F&=ma\\
K&=\frac{1}{2}mv^2
\end{align}
%
\lipsum[2]

\end{multicols}
\end{document}

Example Output: