3

Using the multicol package, I get a layout like this: I would like all columns to be aligned properly. I have tried using tables and arrays, but they won't allow my equations to be numbered. (I need to be able to reference them later)

The Problem

Here is my code:

\begin{equation}
F_{net} = m_0 a_{net}
\end{equation}
\begin{multicols}{2}
\[F_x = m_0 a_x\]
\[a_x = \frac{\mathrm{d}^2x}{\mathrm{d}t^2} = \frac{F_x}{m_0} = 0\]
\begin{equation}
\frac{\mathrm{d}^2x}{\mathrm{d}t^2} = 0
\end{equation}
\[F_y=m_0 a_y\]
\[a_y = \frac{\mathrm{d}^2y}{\mathrm{d}t^2} = \frac{F_y}{m_0} = -g\]
\begin{equation}
\frac{\mathrm{d}^2y}{\mathrm{d}t^2} = -g
\end{equation}
\end{multicols}
These two second order differential equations can be split into four first order differential equations.
\begin{multicols}{4}
\begin{equation}
\frac{\mathrm{d}x}{\mathrm{d}t} = v_x
\end{equation}
\begin{equation}
\frac{\mathrm{d}v_x}{\mathrm{d}t} = 0
\end{equation}
\begin{equation}
\frac{\mathrm{d}y}{\mathrm{d}t} = v_y
\end{equation}
\begin{equation}
\frac{\mathrm{d}v_y}{\mathrm{d}t} = -g
\end{equation}
\end{multicols}

SOLUTION

I wanted to post this for others, if you \usepackage{amsmath}, the align environment provides a much more elegant solution.

The two second-order differential equations shown in \vref{eq:2nd-comp} can be split into four co-dependent first-order differential equations. This is done in order to write the equations in finite difference form.

\begin{align}
&\frac{\mathrm{d}x}{\mathrm{d}t} = v_x & &\frac{\mathrm{d}v_x}{\mathrm{d}t} = 0 & &\frac{\mathrm{d}y}{\mathrm{d}t} = v_y &                         &\frac{\mathrm{d}v_y}{\mathrm{d}t} = -g
\end{align}
2

I'm not sure about the wisdom of using multicols environment to achieve this effect. Nevertheless, just add some line breaks between the equations, as here:

\documentclass{article}
\usepackage{multicol}%% env-> \begin{multicols}
\pagestyle{empty}
\begin{document}
\begin{equation}
F_{net} = m_0 a_{net}
\end{equation}
\begin{multicols}{2}

  \[F_x = m_0 a_x\]

  \[a_x = \frac{\mathrm{d}^2x}{\mathrm{d}t^2} = \frac{F_x}{m_0} = 0\]

  \begin{equation}
  \frac{\mathrm{d}^2x}{\mathrm{d}t^2} = 0
  \end{equation}

  \[F_y=m_0 a_y\]

  \[a_y = \frac{\mathrm{d}^2y}{\mathrm{d}t^2} = \frac{F_y}{m_0} = -g\]

  \begin{equation}
  \frac{\mathrm{d}^2y}{\mathrm{d}t^2} = -g
  \end{equation}

\end{multicols}
These two second order differential equations can be split into four first order differential equations.
\begin{multicols}{4}
  %\abovedisplayskip0pt
  %\abovedisplayshortskip0pt

  \begin{equation}
  \frac{\mathrm{d}x}{\mathrm{d}t} = v_x
  \end{equation}

  \begin{equation}
  \frac{\mathrm{d}v_x}{\mathrm{d}t} = 0
  \end{equation}

  \begin{equation}
  \frac{\mathrm{d}y}{\mathrm{d}t} = v_y
  \end{equation}

  \begin{equation}
  \frac{\mathrm{d}v_y}{\mathrm{d}t} = -g
  \end{equation}

\end{multicols}

\end{document}

enter image description here

Without the line breaks, LaTeX thinks those equations are all embedded in the same paragraph. So the spacing is different above those in the middle of a paragraph as compared with the leading equation, which is seen as starting its own paragraph.

Incidentally, the two commented out lines for \abovedisplayskip and \abovedisplayshortskip can be useful for tweaking spacing issues too. But they are not necessary in this context.

Instead of using the multicols environment, you could use the aligned environment (you'll need to load the amsmath package):

\documentclass{article}
\usepackage{multicol}
\usepackage{amsmath,amssymb}
\pagestyle{empty}
\begin{document}

\begin{equation}
F_{net} = m_0 a_{net}
\end{equation}
\begin{align}
  \notag
  F_x &= m_0 a_x &
  F_y &=m_0 a_y \\[3ex]
  %%
  \notag
  a_x = \frac{\mathrm{d}^2x}{\mathrm{d}t^2} &= \frac{F_x}{m_0} = 0 &
  a_y = \frac{\mathrm{d}^2y}{\mathrm{d}t^2} &= \frac{F_y}{m_0} = -g \\[3ex]
  %%
  \frac{\mathrm{d}^2x}{\mathrm{d}t^2} &= 0 &
  \frac{\mathrm{d}^2y}{\mathrm{d}t^2} &= -g
\end{align}
These two second order differential equations can be split into four first order differential equations.
\begin{align}
  \frac{\mathrm{d}x}{\mathrm{d}t}   &= v_x  &
  \frac{\mathrm{d}v_x}{\mathrm{d}t} &= 0    &
  \frac{\mathrm{d}y}{\mathrm{d}t}   &= v_y  &
  \frac{\mathrm{d}v_y}{\mathrm{d}t} &= -g   
\end{align}

\end{document}

enter image description here

1

You can use minipage environment in multicolumn. It follow that:

\begin{multicols}{2}
\begin{minipage}{0.5\linewidth}
\[F_x = m_0 a_x\]
\[a_x = \frac{\mathrm{d}^2x}{\mathrm{d}t^2} = \frac{F_x}{m_0} = 0\]
\begin{equation}
\frac{\mathrm{d}^2x}{\mathrm{d}t^2} = 0
\end{equation}
\end{minipage}

\begin{minipage}{0.5\linewidth}
\[F_y=m_0 a_y\]
\[a_y = \frac{\mathrm{d}^2y}{\mathrm{d}t^2} = \frac{F_y}{m_0} = -g\]
\begin{equation}
\frac{\mathrm{d}^2y}{\mathrm{d}t^2} = -g
\end{equation}
\end{minipage}
\end{multicols}
These two second order differential equations can be split into four first order    
differential equations.
\begin{multicols}{4}
\begin{minipage}{0.8\linewidth}
\begin{equation}
\frac{\mathrm{d}x}{\mathrm{d}t} = v_x
\end{equation}
\end{minipage}
\begin{minipage}{0.8\linewidth}
\begin{equation}
\frac{\mathrm{d}v_x}{\mathrm{d}t} = 0
\end{equation}
\end{minipage}
\begin{minipage}{0.8\linewidth}
\begin{equation}
\frac{\mathrm{d}y}{\mathrm{d}t} = v_y
\end{equation}
\end{minipage}
\begin{minipage}{0.85\linewidth}
\begin{equation}
\frac{\mathrm{d}v_y}{\mathrm{d}t} = -g
\end{equation}
\end{minipage}
\end{multicols}
0

SOLUTION

I wanted to post this for others, if you \usepackage{amsmath}, the align environment provides a much more elegant solution.

\begin{align}
 \frac{\mathrm{d}x}{\mathrm{d}t}   &= v_x & 
 \frac{\mathrm{d}v_x}{\mathrm{d}t} &= 0 & 
 \frac{\mathrm{d}y}{\mathrm{d}t}   &= v_y & 
 \frac{\mathrm{d}v_y}{\mathrm{d}t} &= -g
\end{align}

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