Problem with brackets

Question

I need to get {}. So what is wrong with the command $ \left\lbrace \left\rbrace $ ?

Answer 1

As mentioned above you have \left \right not applied correctly. A good answer to the application, you can find here. On CTAN, check: beginlatex – A beginner's guide to LaTeX. This guide, now known as “For­mat­ting in­for­ma­tion”, is a well-re­spected in­tro­duc­tion to the use of LaTeX.

You can manipulate the distance between brackets. With \left and \right command the clamp is adjusted dynamically. See code.

\documentclass{article} 
\usepackage{amsmath} 
\begin{document}
\obeylines
$\{\}$
$\{\,\}$
$\{\:\}$
$\{\;\}$
$\{\quad\}$
$\{\qquad\}$\\
$\{A + B = \frac{1}{2}\left[ \frac{\frac{1}{2}}{\frac{1}{2}} \right]\}$\\
$A+B=\left\{\frac{1}{\frac{a b}{c}}\right\}$\\
$A+B=\left\{\frac{\frac{A+B}{\sin (x)}+1}{A+\frac{C+D}{x^{1/y}}}\right\}$
\end{document}