# How to type log functions to a specific base using the math exchange [duplicate]

Say, I want to type log3 to the base 30, which LaTeX command should I use for it?

• @T.Bongers It seems to me the specific question is not answered in that post at all. Indeed, a search for "log" comes up empty for me (except for spurious matches with blog and terminology etc). [One would have to infer it from 11, except that the underscore there displays in such a way that it seems not suitable, so that one would have to take this from still somewhere else.]
– quid Mod
Mar 21 '16 at 18:11
• @quid Hopefully, before reading the point 11, one would read the point 4 and be satisfied with it. I just added an example so that it's clear that subscripts are not only for indices. Mar 29 '16 at 7:04
• @Jean-ClaudeArbaut thank you for the contribution. Still I continue to think that it is unreasonable to close on sight without further consideration, every basic MJ question as dupe of that thread. Even with your addition one still needs point 5 too. Plus, it used to be unclear that \log exists as a command at all. In addition, it'd be plausible it exists with \sqrt like syntax.
– quid Mod
Mar 29 '16 at 7:59
• @quid Mostly agreed. However, I expect people do their "homework" before asking: if the OP tries a quick search with Google, he will find an answer. It's what I do first when I have a LaTeX question, and it often pays. On the other hand, it's precisely the role of StackExchange sites in general to provide this kind of help, so I vote to reopen. Mar 29 '16 at 8:09

I'd type it as $\log_{30}3$ or $\log_{30}(3)$ for $\log_{30}3$ or $\log_{30}(3)$, respectively.