# What are the most common mistakes that beginners of (La)TeX and Friends make?

I want to collect the most common mistakes, misconceptions, pitfalls, etc that (La)TeX and Friends users make. Please one answer for each mistake, misconception, pitfall, etc.

I am only interested in more technical, objective cases rather than psychological, social, subjective cases.

From this complete infinite list of technical and objective cases, we can have a reference how to teach newbies much better directly or indirectly via writing a good book.

The technical and object cases are, for example, as follows.

• Beginners sometimes use $\huge E=mc^2$ with the hope they will get a huge formula. It actually does not produce the expected result. The correct way is \huge $E=mc^2$.
• Beginner sometimes use longtable inside table because they assume longtable is the longer version of tabular which is able to be sandwiched in table.
• etc.
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Not reading an introduction and package documentation. –  Marc van Dongen Oct 21 '13 at 11:36
Aside from answering questions on this site when I don't have a clue what I'm talking about? –  Jubobs Oct 21 '13 at 12:25
There is a similar Community poll on meta: meta.tex.stackexchange.com/a/1596/2693 –  Alan Munn Oct 21 '13 at 13:21
I don't really see how this can get sensible answers, I voted to close as "too broad". As @AlanMunn says the question on meta is perhaps a more suitable location (although it is not really a meta question about the site either) –  David Carlisle Oct 21 '13 at 13:53
Isn't this a sort of "everyone rant here" question? –  marczellm Oct 22 '13 at 21:28
show 15 more comments

Another common misbehavior is reading package or class documentations from TeX mirrors (the worst case, they read from sites with obsolete contents) even though they already installed the complete, up-to-date packages and classes.

I mean that they don't know that texdoc <package-name> invoked in their own machine can launch the documentation in question.

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Several days ago I taught my students how to plot some functions that are either algebraic or transcendental. As usual I introduced them to PSTricks for the sake of its full support for PostScript language.

All functions are expressed in infix form. Some of my students got confused with the algebraic key. They assumed that this key must be enabled via algebraic=true whenever they plot algebraic functions and set it to false whenever they plot transcendental functions. The code they wrote is more and less as follows.

\documentclass[pstricks,border=12pt]{standalone}
\usepackage{pst-plot}
\def\AlgeFunc{x^2-4} % an example of algebraic function
\def\TransFunc{sin(x)} % an example of transcendental function

\begin{document}
\begin{pspicture}(-3,-5)(3,2)
\psplot[algebraic=true]{-2}{2}{\AlgeFunc}
\psplot[algebraic=false]{-2}{2}{\TransFunc}
\end{pspicture}
\end{document}


Actually the algebraic key was created by PSTricks maintainers to allow users to switch from postfix expression (the default in PSTricks) to the infix one or vice versa by setting this key to either false (default) or true.

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One mistake newbies can make is that of having text (in math mode) that extents outside then range of the document.

For example when trying to define Abstract Data Types with many sorts and constructors,the whole line would go until some of the text is just spilling over to the outside of the margin.

One solution would be to use the landscape or geometry package and choose margins that accommodate the work

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Personally I think, it is not to care if a given solution is deprecated. So the nag package, as "old habits die hard" and those are too much widespread all over the web.

Last but not least, not to search tex.stackexchange.com which helped me more than a hundred times so far. It helps to distinguish high value answers from bad code snippets in some boards.

I think anything else has been said, already.

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The first error for many TeX newbies is not backslashing figure brackets in formulae, when it should be backslashed. So they get $\min {x, 100 - x}$ or even $min {x, 100 - x}$ instead of $\min \{\, x, 100 - x\,\}$.

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Attempting to use \ifeven...\else...\fi that actually does not exist. Note that only \ifodd...\else...\fi is available. Probably Knuth likes odd things.

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The mistake I always make, even to this day, is forgetting that newlines have syntactic meaning in LaTeX. I'm so used to using empty lines to delimit my text that I do it automatically, and then end up with ugly text (especially when indentation of the first line is enabled).

The other mistake I always make is forgetting when some command requires arguments, like \array, and then it automatically eats up the first thing after it, leading to the "why isn't it rendering the first element of my matrix?"

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The biggest error is not to use vim as an editor.