[Tex/LaTex] How to use units in this equation

math-modesiunitx

I want to show some units in a fraction in math mode. It includes the following units: gram, squared meter, second, and molar mass. After searching the web, I understood that I should use load \usepackage{siunitx} with appropriate option in \siset{...}. The framework of the desired code should be something like this:

\usepackage{siunitx}
\sisetup{...}
$\frac{\SI{1}{\gram\meter^{2}\sec^{-1}}}{\SI{10}{\gram\mol^{-1}}}$

But, to add these units, I don't know what I should put in {...} for \siset. Thanks in advance.

Best Answer

it is not clear, what is your problem. to show your math expression with units you not need any presetting of siunitx. however, your expression i would rather write on the following way:

\documentclass{article}
\usepackage{siunitx}

\usepackage[textmath, active, tightpage]{preview}% for see only equation
                                                 % (don't use in real document)
\setlength\PreviewBorder{1em}

\begin{document}
\[
X=\frac{\SI{1}{\gram\square\metre\per\second}}{\SI{10}{\gram\per\mol}}
\]
\end{document}

Related Solutions

[Tex/LaTex] How to format SI units

inter-unit-product is an available option and described in the documentation. To get correct spacing you should use ${}\cdot{}$ . However I prefer a tighter spacing by $\cdot$ .

\documentclass{article}
\usepackage{siunitx}
\parindent0pt
\begin{document}
\SI[inter-unit-product =$\cdot$]{1.0}{\newton\meter}\\
\SI[inter-unit-product =${}\cdot{}$]{1.0}{\newton\meter}\\
$1.0\,\mathrm{N}\cdot\mathrm{m}$
\end{document}

enter image description here

To set his behavior for the whole document you can specify the option via \sisetup

\sisetup{inter-unit-product =$\cdot$}

[Tex/LaTex] Why use a package to typeset units

I came to this question thinking "yeah! Why?" but upon reading the currently extant comments and answer I have already changed my tune and am now tending the other way. What I realized, thinking about it and about my small interactions with this package, is that it provides much the same service within LaTeX as LaTeX (or even just TeX itself) provides for writing as a whole. To understand that point, consider the alternatives in communicating some math in writing via a computer:

Write it phonetically, as it were. Words are words, of course, but Greek letters are spelled out, or perhaps drawn in some ad-hoc ASCII art, and more complicated formulas are hacked together in an unspecified manner that may or may not be clear from context.
Write it in TeX, in which Greek letters are spelled out in macros, more complicated formulas are hacked together in some possibly awful manner...and then the result is "compiled" into a document making it all look like you had in mind, so no harm done if your source was a little more schematic than you'd have liked.

The siunitx package does exactly this, but instead of math formulas, it does SI-style units. Sure, one could write the same symbols that normally appear in such units as kg or s$^{-1}$, but that can go wrong visually very easily depending on if the unit appears in math mode or not (just imagine how that affects the latter!), or if several units become crammed together, or (egreg's quite valid observation) broken across a line. Then you may decide that instead of s$^{-1}$ you really want /s for the unit of hertz, necessitating a global change of notation.

These are all the kinds of problems that are handled in TeX by defining macros containing your preferred styles for \kilogram and \hertz and so on. The siunitx just organizes the whole project of defining these macros and their relationships to each other, and gives a lot of aesthetic options on top of it.

Basically, it boils down to "Why would anyone want to program their document in the first place?", to which the answer is "It's easier to write well-structured documents that way."

Best Answer

Related Solutions

[Tex/LaTex] How to format SI units

[Tex/LaTex] Why use a package to typeset units

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