# Open interval (a, b) in LaTeX

Symbol Open interval
Type of symbol Mathematics
Package (requirement) No
Argument Yes
Latex command \left(arg1,arg2\right)
Example \left(arg1,arg2\right) → (arg1,arg2)

You can use the keyboard parenthesis key Shift + (, ) to type open interval in a latex document.

\documentclass{article}
\begin{document}
$$(a , \; b)$$
$$(x_1 , \; x_2)$$
$$(\frac{1}{x_2} , \frac{1}{x_1})$$
\end{document}

Output :

In the above quote, you will see that the size of the parenthesis is not adjusting properly when using fractions at open intervals. In this case, you need to use the \left(arg1,arg2\right) command by which the size of the parenthesis will be automatically adjusted as the size of the fraction.

\documentclass{article}
\begin{document}
$$\left(\frac{1}{x_2} , \frac{1}{x_1}\right)$$
$$\left(\frac{1}{a_2} , \frac{1}{b_1}\right)$$
\end{document}

Output :