# Is there a circle symbol?

Is there a circle symbol for the composition of two functions? Or do I have to resort to using other ways to represent that?

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just as a tip, Wikipedia uses LaTeX style markup for their functions. When your press the edit button you can see :[itex](f\circ f)(x) = f(f(x)) = f^2(x)</math> ;) –  Davy Landman Jan 5 '11 at 8:43

It's \circ:

\documentclass{article}
\usepackage{fixltx2e} % To make $$...$$ robust
\begin{document}
$$f \circ f$$
\end{document}

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Ah thanks, but just \circ would have done :) –  wrongusername Jan 5 '11 at 8:20
@wrongusername. Yes, but it's generally considered a good idea to post something compilable. This one was not exactly hard :-) –  Joseph Wright Jan 5 '11 at 8:25

Probably this is a good chance to recall the Detexify website, where you can simply draw the symbol you want, and obtain the needed code.

I'm a bad illustrator, but for me, after drawing the circle, \circ was the first hit.

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Dror: I think it's better to actually name websites so that people know what they're clicking to and also so that they have a better chance of remembering it next time. –  Loop Space Jan 5 '11 at 10:18

○ as is used for (f ○ g)(x) is Alt+9. I just posted this so if someone needed it, it was here.

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Welcome to TeX.SX! If I type 'ALT+9' I get to another Firefox tab in here and in my usual editor nothing happens. I don't think this is a solution/answer to an old question –  Christian Hupfer Nov 15 '14 at 2:51