Problem with defining parenthesis command in Texmaker

Question

I am new to LaTeX and have been trying to redefine the \left( command to become \(. for some reason TeXmaker won't let me do this, it keeps telling me that \( is already defined but then when I type \( in math mode it has a fit. What should I do?

Here is my preamble:

 \documentclass[12pt]{article} 
 \setlength\parindent{0pt}

 \usepackage[T1]{fontenc}
 \usepackage[utf8]{inputenc} % input encoding UTF-8

 \usepackage{amsmath,amssymb,amsthm}

 \usepackage{color}

 \usepackage[margin=3.0cm]{geometry}
 \usepackage{graphicx}
 \usepackage{float}
 \usepackage{array}
 \usepackage{url}
 %
 %
 \newcommand{\D}{\partial} %partial operator

Answer 1

You can overwrite LaTeX's internal definitions easily enough. It really isn't a good idea, though.

\documentclass{article}
\renewcommand\({\left(}
\renewcommand\){\right)}
\begin{document}
\[
\( \frac{a}{b} \)
\]
\end{document}

It would be better to use something like \lp and \rp.

\documentclass{article}
\newcommand\lp{\left(}
\newcommand\rp{\right)}
\begin{document}
\[
\lp \frac{a}{b} \rp
\]
\end{document}