Making Change and Powerful Numbers

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Komentáře • 37

  • @numerodivergence
    @numerodivergence  Před měsícem +8

    "You didn't prove the statement in the thumbnail. Is this clickbait?!!?"
    No... it's homework.
    (there's a solution in the description)

    • @ozargaman6148
      @ozargaman6148 Před měsícem

      If A,B,C can be 1, then the problem is just N=N*1²*1³, so I'm a bit confused as to how this is even a question

    • @numerodivergence
      @numerodivergence  Před měsícem

      Great point. The description already expands on the conditions for the statement that I couldn't fit in the thumbnail. There's a non trivial expansion for each N where A and C are square free. You could disallow some trivial expansions like you presented and the question is whether any other non trivial expansions exist to which the video answers in affirmative

    • @ozargaman6148
      @ozargaman6148 Před měsícem

      @@numerodivergence you're correct but there's always the problem with prime numbers which have to be expressed as A*1²*1³. Since you can restrict that, you end up being able to express all numbers this way

  • @KanakGupta2410
    @KanakGupta2410 Před měsícem +10

    TIL the powerful in powerful numbers doesn't mean they're stronger than other numbers

  • @maniman121
    @maniman121 Před měsícem +8

    Frobenius coin problem? Ahh you mean the chicken mcnugget theorem

    • @numerodivergence
      @numerodivergence  Před měsícem +2

      This probably has many names and no doubt Chicken McNugget is one of the best ones

    • @ozargaman6148
      @ozargaman6148 Před měsícem

      43 mcnuggets😔​@@numerodivergence

    • @numerodivergence
      @numerodivergence  Před měsícem +2

      Although in the McNugget problem, you can have the gcd of the coin denominations not equal to 1

    • @ozargaman6148
      @ozargaman6148 Před měsícem

      @@numerodivergence ik but it's funny

  • @samueldeandrade8535
    @samueldeandrade8535 Před měsícem +1

    Oh my Euler, yes, the delicious reasoning using inverses in mod N is so refreshing, so satisfactory ...

  • @jakeaustria5445
    @jakeaustria5445 Před 20 hodinami

    Thank You

  • @MrRyanroberson1
    @MrRyanroberson1 Před měsícem

    1. 5 threes can become 3 fives for free
    2. 3 threes + 1 => 2 fives
    3. 1 five + 1 => 2 threes
    therefore a continuum is reached at and after 8 (1 three + 1 five => 3 threes => induction) where the 3 threes => 2 fives => 4 threes => 6 fives => ... 2 2^n threes => 3 2^n fives => ...
    a special situation occurs for 7 and below where there aren't enough fives or threes to increment without using negative coins (7 = 10-3, 4 = 10-6, 2 = 5-3), which is usually possible if the person you're making change to has the coins needed to make the negative value.

  • @PotatoImaginator
    @PotatoImaginator Před měsícem +1

    numbers that can be expressed using 3 & 5 are coefficients > 0 of x^n
    in (1+x^3+x^6+...)(1+x^5+x^10+...) ( Combinatorics )

    • @numerodivergence
      @numerodivergence  Před měsícem +3

      Thank you for the comment. Yeah, that's right! I didn't talk about generating functions which you mention. You also get a nice formula for the generating function as a reciprocal of a quadratic polynomial

    • @PotatoImaginator
      @PotatoImaginator Před měsícem +1

      @@numerodivergence Yes :)

  • @DanDart
    @DanDart Před měsícem

    I'm used to seeing f and g as functions - x/y or a/b as other things.

  • @yashijainj8032
    @yashijainj8032 Před měsícem

    Loved this ❤

  • @samueldeandrade8535
    @samueldeandrade8535 Před měsícem

    Great video!

  • @connorwilcox146
    @connorwilcox146 Před měsícem +2

    Clicked purely cuz of the Hades reference

  • @Qermaq
    @Qermaq Před měsícem

    6:50 even simpler, all the even exponents go to the f^2 and of the odd exponents 3 go with g&3 and the rest go with f^2. So if n = a^2 * b^3 * c^4 * d^5, p would be a * c^2 * d, and g would be b * d.

    • @numerodivergence
      @numerodivergence  Před měsícem

      That's true, and your process is basically the algo in the video showcased for the simple case. The video tackles the general question and the question posed is a very simple corollary as you pointed out

  • @DanDart
    @DanDart Před měsícem

    Ohh, "power-ful". Full of powers. Very good. *Sigh and facepalm* why did I expect something better from mathematicians (disclaimer: I'm a mathematician)

  • @joefarrow1599
    @joefarrow1599 Před měsícem +1

    Your result that 'there exists z such that A z = 1 (mod b)' is only true for all A if b is prime. For example, A = 2 b = 4 has no such solution for z. So I think the proof must be more complex than what you've shown.

    • @adityakhanna113
      @adityakhanna113 Před měsícem +1

      Hi! Thanks for the comment. The hypothesis is that "a and b are coprime" where coprime means that they share no factors other than 1 ofc. 2 and 4 share the factor 2 and aren't coprime
      So when they don't share any factors like 14 and 15, the result is true
      Your statement is actually stronger in the sense that *all* numbers mod b have inverses when b is prime. A more general form of that result is the coprime one stated in the video! Thanks for bringing this up

    • @samueldeandrade8535
      @samueldeandrade8535 Před měsícem

      1:13 "Throughout this video, we will assume A and B are coprime"
      His result that 'there is z such that Az=1 (mod B)' is TRUE because he said gcd(A,B)=1.
      "Throughout this video ... A and B are coprime"

    • @joefarrow1599
      @joefarrow1599 Před měsícem +1

      @@samueldeandrade8535 yes I missed this constraint

  • @user-pr6ed3ri2k
    @user-pr6ed3ri2k Před měsícem

    wait what
    I didnt know you could make all numbers given 2 presumably coprime coins

    • @adityakhanna113
      @adityakhanna113 Před měsícem

      All numbers except a finite few in the beginning

  • @lokamruthk.r7338
    @lokamruthk.r7338 Před měsícem +1

    Not saying this video has it but mumble rap counts as music :)

    • @nikhiljoshi2961
      @nikhiljoshi2961 Před měsícem

      i agree, but mumble rap doesn't exist: the music you're talking about is actually a plethora of sub-genres like trap. the term "mumble rap" was created by white people who do not understand rap as a genre or how art works.

    • @stefanalecu9532
      @stefanalecu9532 Před měsícem

      Are we doing random opinions nowadays?

    • @numerodivergence
      @numerodivergence  Před měsícem

      Sorry to whoever took it seriously. This is just an inside joke :)