[Tex/LaTex] Aligning multiple lines of text in an align environment

align

I want to use the right side of an aligned environment to present the reason for the next line.
If the explanation requires more than one line the alignment fails.
This could be eye-balled by adding a horizontal space but there should be a better way.

How can this be fixed?

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
  a + b &= \quad \text{short reason} \\
  c + d &= \quad \text{a really long and} \\
        &\phantom{=} \quad \text{complicated reason} \notag \\
  e + f \text{.}
\end{align}
\end{document}

If you compile the above code you will see what I mean.
I can't figure out how to add compiled code to a question.
If you know how do add compiled code to the question, please do so.

Best Answer

One option is to use the aligned construct for the multi-line comments as below.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{align}
  a + b &= \quad \text{short reason} \\
  c + d &= \quad \begin{aligned}[t]&\text{a really long and} \\
                                   &\text{complicated reason}\end{aligned}\\
  e + f \text{.}
\end{align}
\end{document}

Related Solutions

[Tex/LaTex] Left aligning equations without align character

Don't use align. Use gather instead.

\documentclass[fleqn]{article}
\usepackage{amsmath}
\begin{document}
\begin{gather}
b := (a \oplus s_1) \oplus s_2 \\ 
e := 0
\end{gather}
\end{document}

[Tex/LaTex] Aligning multiple lines in long equations and arranging the line breaks in `\align` environment

You should use split inside equation for this:

\documentclass{article}
\usepackage{amsmath}

\begin{document}

\begin{equation}
\begin{split}
\pi^{(1)}_{i j}
={}&  -\frac{1}{4}\eta^{\lambda \sigma} ( \eta^{\mu \alpha}\eta^{\nu \beta} + \eta^{\mu \beta}\eta^{\nu \alpha}  ) \biggl\{ \frac{1}{2}\delta_{\lambda 0}( \delta_{\mu i}\delta_{\nu j} + \delta_{\mu j}\delta_{\nu i}  )   \biggr\} \partial_{\sigma} h_{\alpha \beta}
\\
   & -\frac{1}{4}\eta^{\lambda \sigma} ( \eta^{\mu \alpha}\eta^{\nu \beta} + \eta^{\mu \beta}\eta^{\nu \alpha}  ) \biggl\{ \frac{1}{2}\delta_{\sigma 0}( \delta_{\alpha i}\delta_{\beta j} + \delta_{\alpha j}\delta_{\beta i} )  \biggr\} \partial_{\lambda} h_{\mu \nu}
\\
={}& -\frac{1}{4}\partial^{\lambda} h^{\mu \nu}\delta_{\lambda 0}( \delta_{\mu i}\delta_{\nu j} + \delta_{\mu j}\delta_{\nu i} ) -\frac{1}{4}\partial^{\sigma} h^{\alpha \beta}\delta_{\sigma 0}( \delta_{\alpha i}\delta_{\beta j} + \delta_{\alpha j}\delta_{\beta i} )
\\
={}& -\frac{1}{2}\partial^0 h^{i j} - \frac{1}{2}\partial^0 h^{i j}
\\
={}& \dot{h}_{i j}
\end{split}
\end{equation}

\end{document}

The trick is to put = on the left side, following it with {} for ensuring correct spacing.

Avoid useless \left and \right. Also, no \enspace should be used around =.

enter image description here

The number should go in the middle, in my opinion. However, the tbtags option to amsmath will put it at the bottom of a split.

Best Answer

Related Solutions

[Tex/LaTex] Left aligning equations without align character

[Tex/LaTex] Aligning multiple lines in long equations and arranging the line breaks in `\align` environment

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