# Writing equations with fractions and greek letters [closed]

I'm trying to write this equation below and using the \usepackage{amsmath}, but I'm getting the error ! Argument of \frac has an extra } so I still don't know what I did wrong. And how can I make everything upright and not italic?

\begin{eqnarray}
\dot{\varepsilon} = A{\prime}{\prime}{\prime}\dot\frac{\sigma\dot\omega}{k\dotT}\dot\frac{1}{d^2}\left(1+\frac{\pi\dot\delta}{d}\dot\frac{D_{KG}}{D_v} \right)
\end{eqnarray}


## closed as too localized by Seamus, mafp, Mensch, Martin Schröder, WernerMay 26 '13 at 22:58

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. If this question can be reworded to fit the rules in the help center, please edit the question.

• A) Don't use eqnarray, it is not amsmath and evil. It looks like you simply want to use the equation environment here. B) Italic is the usual way to typeset math (but there are packages for upright math, I assume). C) There are a few simple errors in your equation: \dot vs \cdot, \dotT vs \dot T/\cdot T, A''' vs A\prime…. D) I don't get your error. Can we see a minimal working example? – Qrrbrbirlbel May 26 '13 at 21:01
• \dot should be \cdot, except for the first one: \dot produces a dot over the following symbol. For multiplication you need \cdot. Also A''' is to be used for the primes. – egreg May 26 '13 at 21:03
• @egreg thanks to both of you. I removed the eqnarray and used equation and made the changes you both pointed to. So it's working now. I still need to know how to add bold and remove italic effects to my equations. – abdu May 26 '13 at 21:09
• @abdu for boldface math, you can use \mathbf{<symbol>}. Do you want to remove math "italicized" font for all the math expressions (that would be rather unusual), or just for some symbols? – Gonzalo Medina May 26 '13 at 21:16
• @GonzaloMedina you know I've just checked. I just need to remove italic for the greek letters in my equation. I was just looking for a solution. There is this upgreek package but it's not working I think because I'm using amsmath. Any suggestion? – abdu May 26 '13 at 21:24

## 1 Answer

You are using \dot to express a product; \dot is meant to put an accent (a dot) over its argument (as in the first \dot{\varepsilon}); for product you can use \cdot. Don't use eqnarray, but one of the environments provided by amsmath (align, for example). Since your example doesn't require any special alignment, I used a simple equation environment. \prime as a superscript requires ^; so you can write A^{\prime\prime\prime} or simply A'''.

Perhaps this is what you need:

\documentclass{report}
\usepackage{amsmath}

\begin{document}

$$\dot{\varepsilon} = A^{\prime\prime\prime}\cdot\frac{\sigma\cdot\omega}{k\cdot T}\cdot\frac{1}{d^2}\left(1+\frac{\pi\cdot\delta}{d}\cdot\frac{D_{KG}}{D_v} \right)$$

\end{document}


Seeing the font used in the image attached to the question, it seems that the fourier packages was used:

\documentclass{report}
\usepackage{amsmath}
\usepackage{fourier}

\begin{document}

$$\dot{\othervarepsilon} = A'''\cdot\frac{\othersigma\cdot\Omega}{k\cdot T}\cdot\frac{1}{d^2}\left(1+\frac{\otherpi\cdot\otherdelta}{d}\cdot\frac{D_{KG}}{D_v} \right)$$

\end{document}


• I downloaded the fourier.sty because it was missing. But I don't know how to let the terminal find it. Do you I have to copy it somewhere? I'm using TeXLive. – abdu May 26 '13 at 21:53
• @abdu A full installation of TeX Live (from TUG, preferably) includes by default the fourier package. I wouldn't know how to do the installation manually. If you cannot perform a full installation of TeX Live, I suggest you to ask another question regarding the manual installation of just fourier. – Gonzalo Medina May 26 '13 at 22:01
• weird I already have TeX Live 2012 from TUG. Anyways, thank you =) – abdu May 26 '13 at 22:02