[Tex/LaTex] Using Times New Roman

fontsmath-modetimes

enter image description here

  \documentclass[11pt,twoside]{book}

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

    \begin{equation} 
    R_{z} = \frac12 (z \Delta Z)
    \end{equation}

        \end{document}

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

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}

\begin{equation} 
R_{z} = \frac12 (z \Delta Z)
\end{equation}

\end{document}

enter image description here

It does not help. Any idea?

Best Answer

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

enter image description here

enter image description here

If one were to use

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

instead of

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

the result would be

enter image description here