# How to find the right package [duplicate]

Possible Duplicate:
How to find a package name by a command name?

Sorry to ask such a simple question, but I wonder if there is any listing or any site that I can easily find the package for a command. For instance I want to use '\includegraphics{}' but I don't know how to find the appropriate package to use. This question applies in the other way as well. If I want to know what are the functions inside a package.

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## marked as duplicate by Matthew Leingang, lockstep, Hendrik Vogt, Stefan Kottwitz♦Dec 8 '10 at 15:27

you don't need a package to use \mathcal: it just needs to be inside mathmode: $\mathcal{X}$ works fine without any packages... – Seamus Dec 8 '10 at 11:05