What's your favorite math joke that requires at least some amount of higher education in math?

There are three functions hanging out on a street corner. Diverging functions, really badass motherfuckers: 2x, x², and ex. They’re really up to no good. 2x says to x², ‘Oh shit, man, look down the street, differential operator is walking right towards us. If we don’t get out of here, he’s going to differentiate us down to a constant.’ ex is like, ‘Dudes, slow down. I’m ex, and he’s on our turf. I’ll take care of this.’ So ex walks right up to differential operator and says, ‘I don’t think you know what’s up here. Let me introduce myself. I’m ex. What the fuck are you doing on my turf?’ Differential operator looks him up and down and says, ‘Hey, ex, let me introduce myself. I’m the differential operator, with respect to y.’

/r/math Thread