Re: How to read Web pages with funny backslashes?

Stefan Ram schrieb:

  I'm totally out of the loop with what the young'uns are up
  to on the interwebs these days. The other day I stumbled
  across this webpage that said:
 
|Many textbooks, for instance, will tell you that the metric
|tensor of special relativity takes a form like
|
|\[ \eta_{\mu\nu}=\begin{pmatrix}-1&0&0&0\0&1&0&0\0&0&1&0 . . .

If this is mathjax and you copy paste to a text file to compile with a
real LaTeX engine, then in the text file holding he LaTeX code you need
to load packages so that all environments and commands are defined.

E.g., https://de.overleaf.com/learn/latex/Matrices says that the
environment pmatrix is defined by the package amsmath, so in the
preamble of your LaTeX code you need to load that package, e.g., via
\usepackage{amsmath}

  How am I supposed to make heads or tails of this? I figured
  it was meant to be LaTeX, so I tried to copy it into LaTeX as,
 
|\documentclass[a4paper]{article}
|\begin{document}
|Here's something that caused me undue confusion over the years . . .
|Many textbooks, for instance, will tell you that the metric . . .
|\[ \eta_{\mu\nu}=\begin{pmatrix}-1&0&0&0\0&1&0&0\0&0&1&0\ . . .
 
  , but I got hit with:
 
|! Misplaced alignment tab character &.
|l.12 \[ \eta_{\mu\nu}=\begin{pmatrix}-1&
|                                      0&0&0\0&1&0&0\0&0&1&0\0& . . .
|
|?
 
  .

Is this the only error message you get?

Sincerely

Ulrich