> Who says it's only valid for |x| < 1? Anybody who understands the definition of convergent series. > That series isn't just a cute bit of trivia, it is the

> Who says it's only valid for |x| < 1? Anybody who understands the definition of convergent series. > That series isn't just a cute bit of trivia, it is the basis for signed integer mathematics in your CPU. "True" enough for you? Eh. That's only half true. It's related, certainly, by means of a similarity between 2-adic numbers and two's complement representation, but I'd hardly call it the basis for signed integer mathematics.