I found this interesting. Maybe a few other people here will too. I would have never thought that there is a formula based only on limits and elementary functions that tells whether a given number is rational or irrational. Anyone else think this is cool?(adsbygoogle = window.adsbygoogle || []).push({});

[tex]f(x)=\lim_{m\to\infty}[\lim_{n\to\infty}cos^{2n}(m!\pi x)][/tex]

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# Surprising rational/irrational formula

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