How do you write a vector with an underline instead of an arrow?

Question

I don't like the way the vector with an arrow $\vec{x}$ looks. I would prefer to indicate it with a line underline but when I google it nothing comes up to show me how to do it. Does anyone know?

\documentclass[a4paper,11pt]{article}


\begin{document}

 \vec{x} 

\end{document}

Answer 1

Here is a comparison of a few techniques to represent a vector (not sure about the \overline, \underline ones as I don't think that that is standard usage):

Code:

\documentclass{article}
\usepackage{amsmath} 


\begin{document}
$\vec{x}$  $\overline{x}$  $\underline{x}$  $\mathbf{x}$

$\vec{\mathbf{x}}$  $\overline{\mathbf{x}}$  $\underline{\mathbf{x}}$ 
\end{document}

Answer 2

You can renew the command \vec.

\renewcommand{\vec}[1]{\underline{#1}}

In this case, if you use \vec your vector will be underlined. If you change mind and you want to use a dot or whatever, you can change the definition and all your \vec on the document will automatically change in the next compilation.

\documentclass{standalone}
\usepackage{amsmath}

\renewcommand{\vec}[1]{\underline{#1}}

\begin{document}
\[
   \vec{x} = \cdots % "x" will be underlined
\]
\end{document}