When Math Falls into the Wrong Hands

My brother-in-law recently forwarded an email that contained a lot of images plucked from various degenerate corners of the internet, and he suggested that this one could go into my next book:

I suppose it’s funny enough, and I guess it’s technically a math joke, but there’s a problem.

It doesn’t work.

I know, I know. Most people just read the joke, get the humor that the note’s author has used some odious expression to represent the PIN code, and go on about their day. Plus, I’ve heard that less than 1% of the world’s population has taken calculus, so there aren’t too many people who could actually check the math. Not to mention, how many of them would care enough to do so?

Uh… I can think of at least one person who cares enough.

While it’s certainly egotistical to think that I’m the only one in the intersection, it’s likely offensive to include anyone in the intersection who really wouldn’t want to be. So apologies to Matt Parker, Des McHale, Colin Adams, Ed Burger, or any of the other funny math folks who think they should have been included.

Anyway, where was I? Oh, right. Bad math.

The definite integral in the joke sent by my brother-in-law doesn’t yield a four-digit positive integer.

In fact, it yields a very irrational number with a lot of digits:

-2.58208625277854512796640677001459519299166472798789689499…

So unless the PIN code for that bank card has an infinity of digits, well, this is going to be problematic.

I propose, instead, that the joke be rewritten to use the following:

Would it be less funny? Probably. But at least it’d be accurate.

Not to mention, it would be a significantly more fair to Darling. Honestly, no one should ever have to do integration by substitution.