\documentclass[10pt]{article}
 
\usepackage{amsmath}
 
\begin{document}
 
\begin{align}
  y &= \sin | x | \\
  y &= \sin \mathopen{|} x \mathclose{|} \\
  x &= \sin \left (\frac{1}{2} \right ) \\
  x &= \sin \mathopen{}\left ( \frac{1}{2} \right )\mathclose{}
\end{align}
 
\end{document}