# Change brackets (parentheses) style

This might be a bit nitpicky of me, but I would like to replicate the following style of the brackets shown in the pictures below:

The code I used generates the equations that look like this:

The brackets don't seem to be as "sharp" as I want them to be, appearing to be rounder, and the code I used to generate the 2nd expression has the superscript too far away from the bracket. Is there any workaround for this, using the mathptmx package?

EDIT: I like the style of the greek letters of the mathptmx package, and would like to maintain them as well, while altering the style of the parentheses, if possible.

\usepackage[margin = 2 cm]{geometry}

\usepackage{mathptmx}
\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{gensymb}

\begin{document}

$$x_{{ }_{\mbox{\scriptsize n+1}}}=\pi+\tan^{-1}\left(\frac{1}{1-x_{{ }_{\mbox{\scriptsize n}}}}\right)$$

$$a_{{ }_{\mbox{\scriptsize n+1}}}=\left(\frac{7+2a_{{ }_{\mbox{\scriptsize n}}}^{\frac{3}{2}}}{3\ln{a_{{ }_{\mbox{\scriptsize n}}}}}\right)^{\frac{2}{3}}$$

\end{document}

• Welcome to TeX.SE. – Mico Sep 20 '20 at 8:03

You may achieve your parenthesis-related stylistic objective by loading newtxtext and newtxmath instead of mathptmx.

Aside: I assume you write x_{{ }_{\mbox{\scriptsize $n+1$}}} because you like to place the subscript term (n+1) quite a bit lower than where TeX places it by default. As the saying goes, one cannot (should not?!) argue about tastes. Nevertheless, do consider writing either x^{\mathstrut}_{n+1} or x^{}_{n+1}. The resulting code is much easier to read (and presumably easier to input too, right?). The differences in vertical offsets are illustrated in the first equation in the following screenshot. The second and third equations employ the x^{}_{n+1}-approach in four instances; I trust none of your readers will be left in the dark as to which items are subscript terms.

\documentclass{article}
\usepackage[margin=2cm]{geometry}
\usepackage{amssymb,amsmath}
%\usepackage{mathptmx}
\usepackage{newtxtext,newtxmath}

\usepackage{gensymb}

$x_{{ }_{\mbox{\scriptsize n+1}}} x^{\mathstrut}_{n+1} x^{}_{n+1} x_{n+1}$

• Thanks for the helpful answer. Though by changing from \usepackage{mathptmx} to \usepackage{newtxtext,newtxmath} the greek symbols (\pi in this case) have changed a lot compared to before, which I still prefer the latter style. Is there any way to use the new parentheses' style while maintaining the style of the greek symbols with mathptmx? Sorry if the fix is obvious, but I'm still a novice at using LaTex – Daryl Hong Sep 20 '20 at 8:41
• @DarylHong - Actually, what you're asking does not have an obvious fix. I, for one, wouldn't know how to go about this. You may want to edit your posting that whereas you're looking to change the shape of the parentheses, you're actually happy with the other features (such as the shapes of Greek letters) of mathptmx and do not wish to change them. – Mico Sep 20 '20 at 8:50