# How to type bold parentheses in math mode?

How can I write bold/very bold parentheses?

I'm using:

\documentclass[journal]{IEEEtran}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{breqn}
\newtheorem{lemma}{Lemma}
\begin{document}
\begin{dmath}
\left( something \right)
\end{document}


However, I want the \left( and \right) to appear bold.

Thanks

\documentclass[journal]{IEEEtran}
\usepackage{amsmath}
\usepackage{breqn}

\begin{document}

\begin{dmath}
\left( something  \right)
\end{dmath}

\begin{dmath}
\boldsymbol{\left(\right.} something \boldsymbol{\left.\right)}
\end{dmath}

\end{document}

• I used your solution above but it gave me small parentheses which unlike \left( did not grow up adaptively in size – Elnaz Apr 24 '15 at 6:31
• @Elnaz I am afraid that is a limitation of this approach. If you use a for example a big smbol like \sum you can use simply \boldsymbol{\Biggl(}\sum \boldsymbol{\Biggl)} ( or \big, \Big or \bigg). – Fran Apr 24 '15 at 7:05