# TeXworks compilation error when using ^ as a plain text

In my TeXworks (MikTeX 2.9) editor, the following file compiles correctly. But when I change sin-1(x) to sin^-1(x) the following error occurs. I thought TeXworks would treat sin^-1(x) just as a plain text if not inside amsmath delimiters $..$, $$...$$ etc.:

! Missing $inserted. <inserted text>$
l.8 Ignore sin^
-1(x) for typesetting
?


.text File:

\documentclass[11pt]{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\begin{document}

This $$a^{4}$$ is a test.
Ignore sin-1(x) for typesetting
Another $$a_3$$ test.

\end{document}


The issue is that LaTeX restricts the usage of some symbols that have a special meaning to the interpreter. For example, because % signals the beginning of a comment, if you want a percent sign in your document, you have to write it as \%. Similarly, you will also need to escape \, #, $, ^, &, ~, _, {, and } in text mode, because these all have special meanings. Specifically, ^ means a superscript in math mode, so $a^2 + b^2 = c^2$ is OK, but the 5^{th} symphony will generate the same error you have, since ^ isn't allowed in textmode without being escaped. To solve this problem, you have a couple options, depending on context and what you want it to look like. 1. You can write sin\^{-1}(x) and keep everything in text mode. 2. You can use \textsuperscript to get a superscript in text mode: sin\textsuperscript{-1}(x). 3. You can put everything in math mode, where it works without issue: $\sin^{-1}(x)$. (Writing \sin instead of sin typesets it upright, which looks better.) 4. If you want it written in monospace, use \verb+sin^-1(x)+. Here's how each of these options looks in the final document. I personally prefer option 3. • Is \, #,$, ^, &, ~, _, {, and } a complete list of special characters in LaTeX that one need to escape in text mode? If not, could some please provide a link to such a list? Following post makes me to believe that this may indeed be the complete list. – nam Dec 25 '15 at 22:58