Prove that if a is rational and not zero, and t is irrational, then a+t and at are irrational.

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  • เผยแพร่เมื่อ 22 พ.ย. 2023
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ความคิดเห็น • 20

  • @adw1z
    @adw1z 7 หลายเดือนก่อน

    Nice video, extremely trivial stuff

  • @akja4271
    @akja4271 8 หลายเดือนก่อน +2

    Nice video, very well explained 👍

  • @irhzuf
    @irhzuf 6 หลายเดือนก่อน

    Pretty good, but to be honest would be more interesting if you did a short proof why rational - rational = rational and rational / rational = rational. When you don't show the definition, prove those things and you just assume then it makes everything pretty obvious, but it is grounded on some strong assumptions.
    So don't take this personally, but I think that if someone proves something pretty elementary then this person shouldn't assume a lot, because it kinda misses the point of doing elementary maths (it is fun, but it cannot be close to being rigorous if it isn't coming from definitions and so on).
    And I'm not saying that I think it would be better if you did everything from definitions, but if you assume too much you make a short video which doesn't really show much thought process except some transformations and logic.
    Still glad you're doing math videos as it grows a niche, but a cool community so wish you luck!

    • @snellbrosmath
      @snellbrosmath  6 หลายเดือนก่อน

      Hey, thanks, man! I will definitely keep your comments in mind.

  • @stopwatcher8930
    @stopwatcher8930 8 หลายเดือนก่อน +3

    I overcomplicated the problem by a lot after seeing that. Tried it similar to the way that one would prove that root 2 is irrational.

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน

      If you are successful with that proof, I'd love to hear your argument!

  • @maelmcd
    @maelmcd 7 หลายเดือนก่อน +2

    Doesn't I mean the set of all imaginary numbers ? (Complex numbers with no real component) I feel like the set of all irrationnal numbers would just be R\Q

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน

      The set of irrational numbers is R-Q. R is a subset of the complex numbers.

    • @adw1z
      @adw1z 7 หลายเดือนก่อน

      There’s different notations and conventions, so yes and ho

  • @pedrojose392
    @pedrojose392 7 หลายเดือนก่อน

    If x and y are rational then
    x+y and x*y are rational
    Assuming that a+t is rational then a+t-a is rational tis rational contradiction as by hipothesis t is irational.
    Assuming that t*ais rational.
    Then t*a*1/a= t is rational, contradiction.

  • @johnnysun6495
    @johnnysun6495 7 หลายเดือนก่อน +1

    Proof by fucking obviousness

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน +1

      Is the proof obvious or the statement, or both?

    • @trompette4485
      @trompette4485 7 หลายเดือนก่อน

      @@snellbrosmathI think he met the statement. I thought the statement pretty obvious, but obvious statements are generally hard to prove.

  • @d7home2129
    @d7home2129 7 หลายเดือนก่อน +1

    I thought of the same proof. But by directly using the definition of rational i.e p/q. And the theorems about integers.

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน

      Would love to see it!

  • @thomaslangbein297
    @thomaslangbein297 7 หลายเดือนก่อน

    a can also be zero in order to make the sentence correct.

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน

      If a=0, then at would be rational.

    • @thomaslangbein297
      @thomaslangbein297 7 หลายเดือนก่อน

      I quickly read the text and misinterpreted at as the English word „at“ in bad English. For only the sum it would be correct what I said, but so, you are right of course.

    • @snellbrosmath
      @snellbrosmath  7 หลายเดือนก่อน +1

      @@thomaslangbein297 Please let me know if I am wrong about something in the future! I want to make sure I make accurate content.

    • @thomaslangbein297
      @thomaslangbein297 7 หลายเดือนก่อน

      @@snellbrosmath👍