e to the pi Minus pi (31 Jan 2007)

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• explain xkcd | 217

Transcript:

Cueball: Hey, check it out: eπ − π is 19.999099979. That's weird.
Black Hat: Yeah. That's how I got kicked out of the ACM in college.
Cueball: ...what?
Black Hat: During a competition, I told the programmers on our team that e^π − π was a standard test of floating-point handlers -- it would come out to 20 unless they had rounding errors.
Cueball: That's awful.
Black Hat: Yeah, they dug through half their algorithms looking for the bug before they figured it out.

Hover text:

Also, I hear the 4th root of (9^{2 + 19}2/22) is pi.