# Using Times New Roman

  \documentclass[11pt,twoside]{book}

\usepackage{array,tabularx}
\usepackage[ngerman,american]{babel}
\usepackage{amsthm,amssymb,mathptmx}
\begin{document}

$$R_{z} = \frac12 (z \Delta Z)$$

\end{document}


I am trying to use Times New Roman, but it looks different than Mathtype:

Using comments from Times new roman font? and compiling with XeLaTeX:

\documentclass[11pt,twoside]{book}
\usepackage[ngerman,american]{babel}
\usepackage{amsthm,amssymb}
\usepackage{fontspec}
\setmainfont{Times New Roman}
\begin{document}

$$R_{z} = \frac12 (z \Delta Z)$$

\end{document}


It does not help. Any idea?

• LaTeX uses the somewhat pervasive standard that latin math letters are presented in italic, as well as lower-case greek letters. The image you show does not obey that standard. If you enclose your LaTeX equation in \mathrm (math-roman) as in \mathrm{R_{z} = \frac12 (z \Delta Z)}, it will be perhaps what you seek (though nonstandard) – Steven B. Segletes Jun 6 '16 at 18:04
• That's because mathptmx doesn't use Times New Roman directly. It's also obsolete, with the suggestion to use newtx. There's always a direct use of Times available via XeLaTeX; see Times new roman font? – Werner Jun 6 '16 at 18:10

Following the advice of Use \mathrm by default, and using the ptm fonts instead, one can get roman math fonts as the default with \DeclareSymbolFont{letters}{OT1}{ptm}{m}{n}.

As mentioned in my earlier comment, roman-style math symbols are not the LaTeX default. While the use of \mathrm{} can overcome the default italics, on a case by case basis, the referenced approach makes the use of roman letters the default in math mode.

EDITED to recover lower-case greeks. The use of the revised letter font in roman messes up the reference to lower-case greeks. That must be manually corrected by defining a greeksymbol font, using the original designation from the mathptmx package, which is {OML}{ztmcm}{m}{it}. Then, each greek letter must be redefined to use the greeksymbol font.

\documentclass[11pt,twoside]{book}
\usepackage{array,tabularx}
\usepackage[ngerman,american]{babel}
\usepackage{amsthm,amssymb,mathptmx}
\DeclareSymbolFont{letters}{OT1}{ptm}{m}{n}
\DeclareSymbolFont{greeksymbols}{OML}{ztmcm}{m}{it}

\DeclareMathSymbol{\alpha}{\mathalpha}{greeksymbols}{"0B}
\DeclareMathSymbol{\beta}{\mathalpha}{greeksymbols}{"0C}
\DeclareMathSymbol{\gamma}{\mathalpha}{greeksymbols}{"0D}
\DeclareMathSymbol{\delta}{\mathalpha}{greeksymbols}{"0E}
\DeclareMathSymbol{\epsilon}{\mathalpha}{greeksymbols}{"0F}
\DeclareMathSymbol{\zeta}{\mathalpha}{greeksymbols}{"10}
\DeclareMathSymbol{\eta}{\mathalpha}{greeksymbols}{"11}
\DeclareMathSymbol{\theta}{\mathalpha}{greeksymbols}{"12}
\DeclareMathSymbol{\iota}{\mathalpha}{greeksymbols}{"13}
\DeclareMathSymbol{\kappa}{\mathalpha}{greeksymbols}{"14}
\DeclareMathSymbol{\lambda}{\mathalpha}{greeksymbols}{"15}
\DeclareMathSymbol{\mu}{\mathalpha}{greeksymbols}{"16}
\DeclareMathSymbol{\nu}{\mathalpha}{greeksymbols}{"17}
\DeclareMathSymbol{\xi}{\mathalpha}{greeksymbols}{"18}
\DeclareMathSymbol{\pi}{\mathalpha}{greeksymbols}{"19}
\DeclareMathSymbol{\rho}{\mathalpha}{greeksymbols}{"1A}
\DeclareMathSymbol{\sigma}{\mathalpha}{greeksymbols}{"1B}
\DeclareMathSymbol{\tau}{\mathalpha}{greeksymbols}{"1C}
\DeclareMathSymbol{\upsilon}{\mathalpha}{greeksymbols}{"1D}
\DeclareMathSymbol{\phi}{\mathalpha}{greeksymbols}{"1E}
\DeclareMathSymbol{\chi}{\mathalpha}{greeksymbols}{"1F}
\DeclareMathSymbol{\psi}{\mathalpha}{greeksymbols}{"20}
\DeclareMathSymbol{\omega}{\mathalpha}{greeksymbols}{"21}
\DeclareMathSymbol{\varepsilon}{\mathalpha}{greeksymbols}{"22}
\DeclareMathSymbol{\vartheta}{\mathalpha}{greeksymbols}{"23}
\DeclareMathSymbol{\varpi}{\mathalpha}{greeksymbols}{"24}
\DeclareMathSymbol{\rho}{\mathalpha}{greeksymbols}{"25}
\DeclareMathSymbol{\varsigma}{\mathalpha}{greeksymbols}{"26}
\DeclareMathSymbol{\varphi}{\mathalpha}{greeksymbols}{"27}

\begin{document}
$$R_{z} = \frac12 (z \Delta Z)$$
$\alpha\beta\gamma\delta\epsilon\varepsilon \zeta\eta\theta\vartheta\iota\kappa\lambda\mu\nu\xi\pi\varpi \rho\sigma\varsigma\tau\upsilon\phi\varphi\chi\psi\omega$
\end{document}


If one were to use

\DeclareSymbolFont{greeksymbols}{OML}{ptm}{m}{it}


\DeclareSymbolFont{greeksymbols}{OML}{ztmcm}{m}{it}