An anonymous reader writes: A 2011 ProPublica series found that the TSA had glossed over the small cancer risk posed by its X-ray body scanners at airports across the country. While countries in Europe have long prohibited the scanners, the TSA is just now getting around to studying the health effects.
We warn the reader in advance that the proof presented here depends on a
clever but highly unmotivated trick.
-- Howard Anton, "Elementary Linear Algebra"