One of the perils of staying on campus late — at least, if you’re like me and prefer to keep your door open to remind yourself that there’s a world outside your windowless little cell — is that confused students will sometimes wander in and hope that you know what they’re talking about.
In this particular case, it turns out that I did know what they were talking about; the one student who came in was taking a class that I taught this past Spring, and thus I’m reasonably fresh on the finer points of double integration. He then wandered off again, only to return a few minutes later with one of his colleagues in tow.
I’m thinking that I should leave campus now for the night, since otherwise my doorway might be too jammed with calculus students for me to escape safely.