6 ms·

Could you give a use case?

• Filligree 7y ago
  All of calculus.
  • roywiggins 7y ago
    It's possible to do quite a lot without infinities in calculus and trigonometry, whether it makes sense to bother is another question. https://en.m.wikipedia.org/wiki/Rational_trigonometry https://en.m.wikipedia.org/wiki/Rational_trigonometry
    • Cogito 7y ago
      > It's possible to do quite a lot without infinities in calculus and trigonometry This is like Stacey King saying "I'll always remember this as the night that Michael Jordan and I combined for 70 points." Pretty much the entire field of Analysis (of which calculus is a part) relies on 'infinities' of some kind. Even if you try to restrict to the rationals, you're still typically working with infinite series of them. You can do some analysis over the rationals, but often this takes the form of Cauchy sequences of rationals which might be cheating. [0] https://math.stackexchange.com/questions/387234/how-far-can-one-get-in-analysis-without-leaving-mathbbq https://math.stackexchange.com/questions/387234/how-far-can-... [1] https://www.dpmms.cam.ac.uk/~wtg10/reals.html https://www.dpmms.cam.ac.uk/~wtg10/reals.html