Even the smartest students occasionally get stumped during an exam. A physics problem concerning the trajectory of a proton caused one young scholar to give up and use the remaining time to devise (and solve!) an original problem. There's no sign that the student was rewarded for his or her endeavor. The fruits of this student's labors, however, have been launched into the tubes of the Internet, where it may find a kind of electronic immortality. This morning it was forwarded to my campus mail box. This afternoon, I post it on my blog. Who knows where else it has appeared? Where will it appear next?
Behold as calculus is used to unmask the Dark Knight! (Observe that the diligent student did not omit the crucial d(bat) from the integral.)