How do cross out text in math mode?

Question

Since \sout does not work in math mode, what can I use instead? I don't want the diagonal strikeout like with cancelf

Answer 1

The package cancel was made exactly for this purpose.

The manual says that there are four different commands:

1. \cancel
2. \bcancel
3. \xcancel
4. \cancelto{<value>}{<expression>}

The first three work in math and text mode, but \cancelto is only for math mode.

And this is what they do

MWE

\documentclass{article}

\usepackage{cancel}

\begin{document}

\(\cancel{f(x)} = \bcancel{4} + \xcancel{5} - \cancelto{45}{60}\)

\end{document}

Answer 2

This answer is heavily based on egreg's comment and he deserves all the credit.

\documentclass{article}
\makeatletter
\newcommand{\linethrough}{\mathpalette\@thickbar}
\newcommand{\@thickbar}[2]{{#1\mkern0mu\vbox{
    \sbox\z@{$#1#2\mkern-1.5mu$}%
    \dimen@=\dimexpr\ht\tw@-\ht\z@+2\p@\relax % The +2 represents the vertical shift of the line.
    \hrule\@height0.5\p@ % The 0.5 represent the thickness on the line.
    \vskip\dimen@
    \box\z@}}
}
\makeatother
\newcommand{\mathstrike}[1]{\ensuremath{\linethrough{#1}}}

\begin{document}
    \mathstrike{f(x) = x^2},\qquad \mathstrike{c_0}, \qquad \mathstrike{f(x) = x^2 + c_0}
\end{document}