# Looking for a certain math symbol

I have a very simple question. I'm wondering how to type a certain symbol in TeX. I've never encountered this symbol before today, and even after perusing the list of TeX symbols I can't find it. I saw a problem like this:

$6<200^\circ-4<50^\circ$


Except instead of <200 the 200 was sort of... in the <. Like the < was to the left and below the 200. Imagine $\sqrt{200}$ but instead of a square root to the left and above, you have a < but to the left and below.

By the way, I tried Detexify.

• I just tried to imagine what you are describing, but my imagination powers are limited. Can post a picture of the sign? – Johannes_B Dec 3 '14 at 17:37
• Package steinmetz? – Luigi Dec 3 '14 at 17:43
• A quick search for phase in the Comprehensive LaTeX symbols list finds it as part of the steinmetz package. So, this is a clear duplicate - the answer would have been found by scrolling through the documentation. – Werner Dec 3 '14 at 18:50
• I voted for reopen: it may be useful reference for future visits. Maybe the OP could edit the title to make it more informative. – Claudio Fiandrino Dec 3 '14 at 18:58
• @Luigi: That's true, and that's why we have How to look up a symbol or identify a math symbol or character? as an FAQ. People should not just use Detexify and give up. They should look at other options and once that's been fully explored, ask a question here. Otherwise I would consider it a duplicate. – Werner Dec 3 '14 at 19:01

You are describing the so called Steinmetz notation for complex numbers (or angle notation): the number on the left is the magnitude, the one on the right is the argument of the complex number. You can use the \phase command from the steinmetz package.

\documentclass{article}
\usepackage{steinmetz}

\begin{document}
$6\phase{200^\circ}-4\phase{50^\circ}$
\end{document} • I'm asking who's the author of this famous package. ;-) – egreg Dec 3 '14 at 22:01
• @egreg, ça va sans dire – Luigi Dec 4 '14 at 7:54

This is just an extension of Luigi's answer where the siunitx package is used to typeset the physical quantities in a consistent way:

\documentclass{article}

\usepackage{steinmetz}
\usepackage{siunitx}

\begin{document}

$6\phase{\ang{200}} - 4\phase{\ang{50}}$

\end{document} • I upvoted your answer. Even better to use the \ang command from the siunitx package. – Luigi Dec 5 '14 at 17:56