A hush descended over the classroom as Inspector McGee strode to the
podium. After all, he had served on the Fraud Squad for over 20 years,
and the talks that he gave to each year's crop of police recruits were
the stuff of legend. No one else had the fund of stories about past
experiences that he did. Each year he amazed the rookies by telling
them of yet another bizarre technique that he had used to unmask the
schemes of the city's con artists. It seemed that there was no branch
of knowledge that he hadn't exploited at some point in his career. But
this year, the rumor went, he was going to outdo himself; somehow he
had actually used calculus to convict a criminal! It seemed hard to
believe. The rookies strained forward in anticipation.