Automatically fit equation in align environment in page width

alignequations

I have an issue in a system I am working on where long equations go beyond the page width. The LaTeX is automatically generated by an algorithm and I would like to have a way to make it fit in the page even if that makes it a little smaller. This solution would be fine for cases where the equation is a little larger than the page width. Obviously for extreme cases the developer will have to split the equation into more equations.

In my estimate it is way harder to make the system automatically recognise positions in an equation where it could split it in more lines.

After going through various posts in this forum (for example this one can i use resize box in align) I have not found a working sample of code using \resizebox in an align environment. How could I resize the following equation for example to fit the page?

\begin{align*}
    N_{Ed0} &= N_x · \cos^2(\phi_0) + N_y · \sin^2(\phi_0) + 2 · N_{xy} · \sin(\phi_0) · \cos(\phi_0) - N_0 · \cot(\phi_0) \\
            &= (-1.81234E3) · \cos^2(47.0113) + (-9.06168E3) · \sin^2(47.0113) + 2 · 28.19E3 · \sin(47.0113) · \cos(47.0113) - 18.4356 · \cot(47.0113) = \mathbf{ 22.4121E3 \: N }
\end{align*}

PS: The decimal points are a user option so the solution could not be "reduce the decimals".

Best Answer

You need a horizontal mode construct in \resizebox I really can not recommend doing this at all as it quickly makes the math unreadable with no warning but:

\documentclass{article}

\usepackage{amsmath,graphicx}
\DeclareUnicodeCharacter{00B7}{\cdot}
\begin{document}
\noindent X\dotfill X
\begin{center}
\resizebox{\textwidth}{!}{$\begin{aligned}
    N_{Ed0} &= N_x · \cos^2(\phi_0) + N_y · \sin^2(\phi_0) + 2 · N_{xy} · \sin(\phi_0) · \cos(\phi_0) - N_0 · \cot(\phi_0) \\
            &= (-1.81234E3) · \cos^2(47.0113) + (-9.06168E3) · \sin^2(47.0113) + 2 · 28.19E3 · \sin(47.0113) · \cos(47.0113) - 18.4356 · \cot(47.0113) = \mathbf{ 22.4121E3 \: N }
\end{aligned}$}
\end{center}
\end{document}

I would drop the alignment and let latex break the inline math with no font scaling

\usepackage{amsmath,graphicx}
\DeclareUnicodeCharacter{00B7}{\cdot}
\begin{document}
\noindent X\dotfill X
\begin{center}
$
    N_{Ed0} = N_x · \cos^2(\phi_0) + N_y · \sin^2(\phi_0) + 2 · N_{xy} · \sin(\phi_0) · \cos(\phi_0) - N_0 · \cot(\phi_0) $\\$
            = (-1.81234E3) · \cos^2(47.0113) + (-9.06168E3) · \sin^2(47.0113) + 2 · 28.19E3 · \sin(47.0113) · \cos(47.0113) - 18.4356 · \cot(47.0113) = \mathbf{ 22.4121E3 \: N }
$
\end{center}
\end{document}

Related Solutions

[Tex/LaTex] Numbering of each equation within cases with left alignment (both on the page and within the equations)

Another solution (and numbering) with the empheq package (which loads mathtools, which loads amsmath):

\documentclass{article}
\usepackage[a4paper,margin=2.5cm]{geometry} % set page parameters
\usepackage{amsfonts, % for \mathbb and \mathcal macros
            empheq}%

\numberwithin{equation}{subsection}
\setcounter{section}{1}
\setcounter{subsection}{1}

\begin{document}

\begin{subequations}
  \begin{empheq}[left={\mathbb{E}(X)=\displaystyle\int_{-\infty}^{\infty} x\,dF(x)=\empheqlbrace}]{alignat = 2}
    & \sum_{x \in \mathcal{X}} xf_{X}(x) =\sum_{x \in \mathcal{X}} x\mathbb{P}(X=x)
    &\qquad & \text{if $X$ is discrete}, \\
    & \int_{-\infty}^{\infty} xf_{X}(x)\,dx
    & &\text{if $X$ is continuous}. \end{empheq}
    \end{subequations}

\begin{subequations}
  \begin{empheq}[left={\mathbb{E}(X)=\displaystyle∫_{-∞}^{∞} x\,dF(x)=\empheqlbrace}]{flalign}
    & ∑_{x ∈ \mathcal{X}} xf_{X}(x) =∑_{x ∈ \mathcal{X}} x\mathbb{P}(X=x)
    & &\text{if $X$ is discrete},&\hspace{5em} & \\
    & ∫_{-∞}^{∞} xf_{X}(x)\,dx
    && \text{if $X$ is continuous}. \end{empheq}
    \end{subequations}

\end{document}

[Tex/LaTex] Getting extra equation numbers using align environment

Just omit the line-break directive at the end of the final equation in a given align group. E.g.,

\begin{align}
    P(t) &= \tfrac{3}{2}[v_d(t)i_d(t)] \\
    Q(t) &= \tfrac{3}{2}[-v_d(t)i_q(t)] % <- no "\\" directive
\end{align}

As the code shows, I would also (a) remove the \left and \right qualifiers as they actually don't do anything for the cases at hand and (b) replace \frac with \tfrac.

If you have a multi-line equation that should be assigned just one equation number, don't use an align environment. Instead, use a split environment inside an equation environment.

By the way, the arrows produced by \overrightarrow look disproportionately large; consider using \vec instead. For arrows (and other diacritics) set above the characters i and j, it's traditional to omit the "dot", i.e., to use a "dotless" i and j; this may be achieved in math mode by writing \imath and \jmath. Separately, I again would not use \left and \right to autosize the round parentheses and curly braces; consider using \bigl and \bigr instead. (By the way, the outermost round parentheses may be omitted in all three rows, right?)

\documentclass{article}
\usepackage{amsmath}
\numberwithin{equation}{section}
\begin{document}

\setcounter{section}{1} % just for this example 
\setcounter{equation}{31}
\begin{align}
    P(t) &= \tfrac{3}{2}[v_d(t)i_d(t)] \\
    Q(t) &= \tfrac{3}{2}[-v_d(t)i_q(t)] 
\end{align}

\setcounter{equation}{20} % just for this example
\begin{equation}\begin{split}
P(t) 
&= \frac{
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)\bigr\} + 
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)^*\bigr\}}{2} \\
&\quad+ \frac{
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)e^{-j\frac{4\pi}{3}}\bigr\} + 
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)^*\bigr\}}{2} \\
&\quad+ \frac{
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)e^{-j\frac{8\pi}{3}}\bigr\} + 
\Re\bigl\{\vec{v}(t)\vec{\imath}(t)^*\bigr\}}{2} 
\end{split}\end{equation}
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Numbering of each equation within cases with left alignment (both on the page and within the equations)

[Tex/LaTex] Getting extra equation numbers using align environment

Related Question