Is there a way to label equations in Latex with words insted of numbers when doing an array?

Question

I'd like to give a reason each line of my equation list follows from.

Hi, I love this question but can you provide a minimal reproducible example so we can try stuff on common base ? — Gowachin, May 19 '21 at 08:27
Can you please make a [mre]? If you are using amsmath, you could use the `\tag` macro — samcarter_is_at_topanswers.xyz, May 19 '21 at 09:03

Gowachin · Accepted Answer · 2021-05-19T19:41:54.350

I have a temporary solution where you add text next to each line.

\documentclass[10pt,a4paper]{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\begin{document}

Basic way to add text to each line.

\begin{align}
x &= 4^{2} - 1 && \text{given}\\
  &= 16 - 1    && \text{exponent}\\
  &= 15        && \\  % line without text
  &= 15        && \text{subtraction}
\end{align}

Better way when removing numbers.

\begin{align*}
x &= 4^{2} - 1 && \text{given}\\
  &= 16 - 1    && \text{exponent}\\
  &= 15        && \\
  &= 15        && \text{subtraction}
\end{align*}

Below, this example put less space between equation and text, and parenthesis.

\begin{alignat}{2}
x &= 4^{2} - 1 && \qquad\text{(given)}\\
  &= 16 - 1    && \qquad\text{(exponent)}\\
  &= 15        &&  \\
  &= 15        && \qquad\text{(subtraction)}
\end{alignat}


\end{document}

This was far too helpful. Cheeeeers! – Hanny Boy May 19 '21 at 18:07 — Hanny Boy, May 19 '21 at 18:07

MattAllegro · Answer 2 · 2021-06-28T21:08:45.700

As in this other answer, you may use the command \tag{}:

\documentclass{article}
\usepackage{amsmath}

\begin{document}
\begin{align}
  x+y\label{eq1}\tag{First one}\\
  x+z\label{eq2}\tag{Second one}\\
  x-y\label{eq3}\tag{Third one}\\
  x-z\nonumber
\end{align}

Then you can cite \eqref{eq1}, \eqref{eq2} and \eqref{eq3} separately.

Or you can cite \ref{eq1}, \ref{eq2} and \ref{eq3}.
\end{document}

See the output of the two styles for the in-text citation:

Is there a way to label equations in Latex with words insted of numbers when doing an array?

2 Answers2