[Tex/LaTex] How to make a multi-line equation fit in a single column of a two-column document

equationsspacing

I am trying to suit a formula to a two-column style document using cases in the flalign.
It nearly fits if an unnecessary space would not prevent. Is their any option to remove it?

\documentclass[3p,times,12pt,draft,twocolumn]{elsarticle}
\usepackage{mathtools}

\begin{document}

\begin{flalign}
E_{\perp,diff}=
\begin{cases}
E_{g,meas}&\cdot(1.020-0.254\cdot k+0.0123\\
&\cdot\sin\gamma_S)  \quad \text{for k $\le$ 0.3}\\
E_{g,meas}&\cdot(1.400-1.749\cdot k+0.177\\ 
&\cdot\sin\gamma_S)      \quad \text{for 0.3 $<$ k $<$ 0.78}\\
E_{g,meas}&\cdot(0.486\cdot k-0.182\\ 
&\cdot \sin\gamma_S) \quad \text{for k $\geq$ 0.78}
\end{cases}
\end{flalign} 
\end{document}

enter image description here

Best Answer

You don't need flalign (I see it too often abused) nor cases, but aligned:

\documentclass[3p,times,12pt,draft,twocolumn]{elsarticle}
\usepackage{mathtools}

\begin{document}

\begin{equation}
E_{\perp,\mathrm{diff}}=
  \left\{
  \begin{aligned}
  E_{g,\mathrm{meas}}
    &\cdot(1.020-0.254\cdot k+0.0123\\
    &\cdot\sin\gamma_S)  \quad \text{for $k\le 0.3$}\\
  E_{g,\mathrm{meas}}
    &\cdot(1.400-1.749\cdot k+0.177\\
    &\cdot\sin\gamma_S)      \quad \text{for $0.3 < k < 0.78$}\\
  E_{g,\mathrm{meas}}
    &\cdot(0.486\cdot k-0.182\\
    &\cdot \sin\gamma_S) \quad \text{for $k \geq 0.78$}
  \end{aligned}
  \right.
\end{equation}
\end{document}

enter image description here

However, I'd split into two parts: one with the main information, the other with the complicated things.

\documentclass[3p,times,12pt,draft,twocolumn]{elsarticle}
\usepackage{mathtools}

\begin{document}

\begin{gather}
E_{\perp,\mathrm{diff}}=E_{g,\mathrm{meas}}\varphi(k,\gamma_S)\\
\varphi(k,\gamma_S)=
  \left\{
  \begin{array}{@{}l@{}}
  1.020-0.254k+0.0123\sin\gamma_S\\
    \hfill\text{for $k\le 0.3$}\\[1ex]
  1.400-1.749k+0.177\sin\gamma_S\\
    \hfill\text{for $0.3 < k < 0.78$}\\[1ex]
  0.486k-0.182\sin\gamma_S\\
    \hfill\text{for $k \geq 0.78$}
  \end{array}
  \right.\notag
\end{gather}
\end{document}

enter image description here

Related Solutions

[Tex/LaTex] How to make this equation fit on a single line

Multiplying the exponentials and factoring out a common expression makes this a little shorter, and perhaps a little easier to read.

enter image description here

If 2/\alpha (which appears five times in your expression) has semantic significance you could consider naming it, say \beta.

\documentclass[a4paper]{article}
\usepackage[showframe,margin=1in]{geometry}
\usepackage{amsmath}
\begin{document}

\begin{equation*}
\text{1\textsuperscript{st} integral} 
= \int_{0}^{\infty}
\frac{2 \pi \zeta}{\alpha} \, t^{(-2/\alpha-1)}
\exp\biggl(- \pi t^{-2/\alpha}
\biggl( \zeta + 
\sum_{i\in K}\frac{\lambda_i P_i ^{2/\alpha}
  \rho(D_i\hat{T}_i,\alpha)}{D_i\hat{T}_i^{2/\alpha}}
\biggr)
\biggr)  
\,dt 
\end{equation*}

\end{document}

[Tex/LaTex] Fit an equation in a single column

It is best to divide this up into smaller elements, the 3x3 matrix is simply too big. Giving names to the columns and writing them out separately provides narrower text. Below I give two version, the first using the convenient amsmath package, the second with standard LaTeX commands. In the standard LaTeX version, note that array is appropriate in math mode, rather than tabular.

Sample output

\documentclass[twocolumn]{article}

\usepackage{amsmath}

\begin{document}

\begin{equation*}
  \begin{pmatrix}
    x_n \\
    y_n \\
    z_n
  \end{pmatrix}
  =
  \begin{pmatrix}    
    v_1& v_2& v_3
  \end{pmatrix}
  \begin{pmatrix}
    x_b \\
    y_b \\
    z_b
  \end{pmatrix}
  ,
\end{equation*}
where
\begin{gather*}
  v_1 =
  \begin{pmatrix}
    \cos\theta\cos\psi \\
    \cos\theta\sin\psi  \\
    \sin\theta
  \end{pmatrix}
  ,\\
  v_2 =
  \begin{pmatrix}
    -\cos\phi\sin\psi +\sin\phi\sin\theta\cos\psi\\
    \cos\phi\cos\psi +\sin\phi\sin\theta\sin\psi\\
    \cos\theta\sin\phi
  \end{pmatrix}
  , \\
  v_3 = \begin{pmatrix}
    \sin\phi\sin\psi +\cos\phi\cos\psi\sin\theta \\
    \sin\theta\sin\psi\cos\phi - \cos\psi\sin\phi \\
    \cos\theta\cos\phi
  \end{pmatrix}.
\end{gather*}

Poorer version in standard LaTeX:
\begin{displaymath}
  \left(\begin{array}{c}
    x_n \\
    y_n \\
    z_n
  \end{array}\right)
  =
  \left(\begin{array}{ccc}    
    v_1& v_2& v_3
  \end{array}\right)
  \left(\begin{array}{c}
    x_b \\
    y_b \\
    z_b
  \end{array}\right)
  ,
\end{displaymath}
where
\begin{eqnarray}
  v_1 &=&
  \left(\begin{array}{c}
    \cos\theta\cos\psi \\
    \cos\theta\sin\psi  \\
    \sin\theta
  \end{array}\right)
  ,\nonumber \\
  v_2 &=&
  \left(\begin{array}{c}
    -\cos\phi\sin\psi +\sin\phi\sin\theta\cos\psi\\
    \cos\phi\cos\psi +\sin\phi\sin\theta\sin\psi\\
    \cos\theta\sin\phi
  \end{array}\right)
  ,\nonumber \\
  v_3 &=& \left(\begin{array}{c}
    \sin\phi\sin\psi +\cos\phi\cos\psi\sin\theta \\
    \sin\theta\sin\psi\cos\phi - \cos\psi\sin\phi \\
    \cos\theta\cos\phi
  \end{array}\right)
  \nonumber.
\end{eqnarray}

\end{document}

See the amsmath documentation for other math environments with differental alignment possibilities.

Best Answer

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