It’s such a failure of our system of math education that people tend to associate irrational numbers with their decimal notation being infinite and non-periodic. Decimal notation is, well, just a notation — whereas the basic, way more natural definition of irrational numbers is that they can’t be expressed as a ratio of two integers.
This doesn’t make it much easier to prove irrationality of pi in a Reddit comment, but it’s the starting point for the sqrt(2) proof which other commenters have kindly provided.
Latest Answers