.9999...=1


  1. Mikestony

    Mikestony ~30% Carbon Black ± Moderator

    You tryin to start a riot with us Indiana folk?:boxing: :p
    ocnbrze likes this.
  2. psionandy

    psionandy Well-Known Member


    Thats a pretty interesting read... and having read it I now think I get whats going on. It appears that 0.999... in the way that mathematicians currently understand it, doesn't actually mean what I thought it did.

    So i'm fine with the whole 0.999... =1 thing. Which is completely different from 0.99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 =1 which it clearly isn't.

    Who says you can't learn anything in pointless conversations :rofl:





    Only the stupid ones....

    (which obviously wouldn't include anyone here)

    :HidingUnderDeskSmiley:
    ocnbrze and scary alien like this.
  3. dan330

    dan330 Well-Known Member

    so.. to recap...

    .9999 not = 1
    but
    .9999... = 1

    cool.. i can accept that.
    psionandy, SUroot and scary alien like this.
  4. SUroot

    SUroot Well-Known Member Developer

    Maths is funny. If a trailing car continually halves the distance between it and the car in front, it will never catch up.
  5. Bob Maxey

    Bob Maxey Well-Known Member

    With the math soltions and skills being demonstrated in this thread by some people, you will also need a good tax lawyer because you be a going to prision.

    .999999 does not equal 1! And .99999999999999999999999999999999999999999999999999999999 does not equal 1, and .999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 does not equal 1 either. Neither does .99999 (on to infinity) equal 1. And remember, infinity is not a number, it is a concept.
    Stinky Stinky likes this.
  6. dan330

    dan330 Well-Known Member

    dear bob,

    in tax.. you round to the nearest $dollar.

    so ..... .99 = 1
  7. jhawkkw

    jhawkkw Chinchillin' Moderator

    If my math skills are wrong, please identify where they are wrong because I'm curious as to why you think so.
  8. Sak01

    Sak01 Well-Known Member

    If you're having math problems I feel sorry for you son
    I got .99 problems but a non-recurring number ain't one
  9. dan330

    dan330 Well-Known Member


    is reading 1?





    :eek:
  10. SUroot

    SUroot Well-Known Member Developer

    You can't do the maths with infinite or reccurring numbers so you must start with a set amount of digits to prove a point. An absolute number.

    Multiply by 10 simply moves the decimal point. It can't conveniently make more digits or decimal places

    X = .999999
    10x = 9.99999

    10x - x = 9x

    Or

    9.99999 - .999999 = 8.999991

    Its not so much that your maths is wrong as it is that maths is wrong in general.
  11. jhawkkw

    jhawkkw Chinchillin' Moderator

    This as written is correct, but fails to take into account that .999... a number of infinite length. Thus require the use of an infinite limit. I'll post the calculus proof by use of infinite series, since there is still non believers once I finish teaching my last class tonight.
  12. Sak01

    Sak01 Well-Known Member

    :D
    Probably but not on this occasion. There was nothing wrong with your maths, it's just the only way I could play on the lyrics:
    99 PROBLEMS - YouTube
  13. dan330

    dan330 Well-Known Member

    yeah.. i got musical theme to your post... funny :p

    but it confers that i have something wrong with my understanding.
    and it should refer to "recurring" not "non-recurring" numbers, since the issue is over "recurring" numbers (.9999...)
  14. SUroot

    SUroot Well-Known Member Developer

    Actually words 7 and 9 of my post take this into account when combined with the rest of the first sentence

    If you look how your maths is written, you have .9999 ad infinitum but when you multiply it by 10, you magically have add infinitum + 1 extra digit, which is why your maths looks to work. But we all know .99999 blah is not actually 1.

    Since infinity isn't really a number, it can't really be used in maths to form any cohesive proof that 1 isn't 1.

    If you massage numbers correctly, you can "prove" anything and you did a good job of massaging them. Well done. But joking aside, .9 reoccurring is nothing except what it is, even if you can make it appear so on paper. Maths is the last bastion of comedy.
  15. jhawkkw

    jhawkkw Chinchillin' Moderator

    You certainly use infinity in math, it's one of the entire foundations of Calculus. The ability to take limits as a variable goes to positive or negative infinity is a subject that comes up in multiple topics such as horizontal asymptotes, anti-derivatives/integrals, improper integrals, and sums of infinite series. For the record, I am a college mathematics professor who teaches these topics in Calculus I & II. I never claimed to be good with taxes, just with mathematical theory. I noticed that people picked apart my algebraic proof with skepticism, but flat out ignored my proof through analysis most likely because very few ever take 4th year mathematics courses when single variable calculus is considered to be first year. As promised, I am going to provide the proof that anyone who has taken calculus II could do by use of the Geometric Series. Just so people don't think I pull formulas out of thin air, I'm actually going to use a formula in this proof that you can look up in any calculus textbook, and I will even cite one, James Stewart's Calculus Early Transcendentals 5th Edition(ISBN:0-534-39321-7). Because the proof requires the use of symbols not easily typed, I have hand written it and attached it to this. Hopefully this will be much more convincing.

    Attached Files:

    • Scan.jpg
      Scan.jpg
      File size:
      258.3 KB
      Views:
      38
  16. Sak01

    Sak01 Well-Known Member

    So the recurring number in question IS one ( .999... = 1)
    But a non-recurring number ain't "one" (.999 =/= 1)

    Which is what you correctly stated.

    I've heard a puppy gets strangled every second a bad joke gets dragged out so I better cease and deactivate.
  17. SUroot

    SUroot Well-Known Member Developer

    Thanks for posting that. I know that infinity is used in maths. I think you're missing my point. I did not say your maths was wrong. I said maths in general is wrong. I am completely comfortable arguing this with a college mathematics professor. In fact, thats all the more poignant.

    1 is 1. .9999' is not 1. I am using ' as the symbol for recurring as there isn't one.

    We cannot use infinity to prove something that is not 1 is actually 1. Infinity is not a number. It is s concept. Recurring numbers do not actually exist. If I have 9 cakes, I can share them between 3 people equally. If I have 2 people, cutting the cake is possible. If I have 10 cakes and 3 people, cutting the cake wont work. It is physically not possible.

    Recurring numbers exist so from a mathematical stand point, it is possible when in reality we know the contrary to be true.

    So now we have a series of equations that attempt to prove .9999' is equal to 1. The mathematics behind it stands up. My point is, that is irrelevant. Using a non-existant number in an equation to prove that something that really exists is in fact something else, wont wash.

    Mathematics is hugely flawed and even the greatest mathematical minds of our time still do not understand it fully. We know 1 is 1. We know .9999' is not 1. We cannot use mathematical flaws (the use of things that cannot exist) to prove otherwise. If all it is doing is "proving" that the opposite of reality is true (incorrectly) then it's use of proving anything lessens significantly. Its credibility is lost.

    So you see, its not me against you. Its reality against maths. .9999' is the closest you can get in maths to 1 without being 1 and no amount of mathematical loop holes will change that.

    Maths exists in reality and has its uses in everyday life. I do not deny. How else will I share cakes fairly or count in binary?! However as infinity is a concept and not a reality, regardless as to whether we can use it to show something that doesn't exist is the same as something that does exist, doesn't make it conclusive or even correct. You can only use existing numbers in reality to prove conclusively, which I've already shown proves the opposite and that my good man, is my point.
  18. Xyro

    Xyro 4 8 15 16 23 42 Moderator

    There are 10 types of people in this world. Those that understand binary, those that don't and those that didn't expect this joke to be in base-3.
    Mehta23 likes this.
  19. jhawkkw

    jhawkkw Chinchillin' Moderator

    Nice spin Xyro, I don't think I've ever seen that classic that way. I'll have to remember that alternate.

    1st point: you might not have intended or realized this, but this indirectly proves my point. I'll get to it after number 2.

    2nd point: repeating numbers exist because of division. You slightly hint at this with the cake reference, but is an unwanted consequence of dividing by certain prime numbers. Also, not every decimal that is infinite in length is a repeating number. The two most famous ones being PI (the ratio between a circle's circumference and diameter), or e (the base of the natural logarithm).

    Back to number 1, which is an expansion on a slightly less rigorous method shown earlier.. The cake problem is exactly how defining 1/3 comes about. If you attempt to define 1/3 in decimal form, it becomes a never ending attempt of dividing 3 into 10. You will always get 3 with a remainder of 1, and thus have to bring down another 0 and create a brand new 10, and the resulting decimal is .333... or .333` as you last wrote. Extrapolate that problem to 2/3. This ones again turns into a never ending problem, but this time trying to divide 20 by 3, which results in 6 with a remainder of 2, forcing you to bring down the next zero. These numbers do not terminate because the division never terminates, not because we don't want them to or because it is convenient for them to continue on forever, it's because that's how the algorithm is done. In conclusion, simple addition of 1/3 + 2/3 would get us 3/3 or 1. since .333... and .666... only contain 3s or 6s and. There is no 4 in 1/3 or 7 in 2/3 at the end of the tunnel,and 3+6 is nine, so the result of adding .333... (1/3)and .666... (2/3)would give us .999... (3/3=1). And while not everything can be easily cut into thirds, one thing that can be cut into thirds are circles into into 3 120 degree parts.

    Point 3) All of the great mathematical minds accept the fact that .999... = 1, which is why this particular problem in relation to accepting it to be true is studied, because it puzzles us mathematicians why people cannot accept it to be true when the math is 100 percent sound. In fact, math is one of the only things that is ABSOLUTE. The 5 basic operators(+-*/^) don't just work in some cases and not in others. If you follow the rules of math, it will always work out and will always be correct, granted, not everyone knows all the rules as evident in many papers I grade :p. If you drive at a constant rate of 60mph, for exactly 2 hours, you will drive 120 miles. not 119, not 121, but exactly 120. . Mathematicians might not have discovered or proved everything in math, such as the P=NP question, the Riemann Hypothesis, or any of the other millennium questions, but what has been proven is FACT.

    Accepting things to be true that don't intuitively seem to be true is tough. I was the same way when I was in school with certain topics, such as the total number of integers and rational numbers (fractions) are equal until I saw the proof using the Cantor pairing function (it's actually quite elegant) .
  20. SUroot

    SUroot Well-Known Member Developer


    All I'm going to say is show me .3333' of a cake :)
  21. jhawkkw

    jhawkkw Chinchillin' Moderator

    In some cases it can be done easily, like a cake of length 12 inches can be cut into 3rds with length 4, or a circular cake (like a wedding cake) of 120 degrees. But for lengths that are not a multiple of 3, we has humans do not tools precise enough to make the cut exactly equal 3rds.
    In the end, the practicality of the argument does seem worthless. But just because something is worthless doesn't make it untrue. What an ugly double negative:eek:.
  22. SUroot

    SUroot Well-Known Member Developer

    heheh fair enough.
  23. big_z

    big_z Well-Known Member

    Part of your problem is that you think there are non-existent numbers.

    1/3 is not a non-existent number. It is impossible to represent finitely as a decimal number. That's a simple way of saying that it is impossible to represent as a finite sum of powers of 10. If, however, you were to think in terms of base-3, 1/3 is neatly represented as .1

    To say that something is not a number simply because it can't be finitely represented in the base system of your choice would be to end computer math as we know it, because there are a *lot* of numbers that can't be finitely represented as powers of 2. 1/5 (.2) is one such number. The nice and neat .2 in decimal is represented by the infinitely repeating (and in your world, "nonexistant") .0011001100110011...
    (note, I am well aware that computers don't represent floating point numbers this way).

    Man, it's really going to blow some of your minds when you learn that e^i*pi = -1, where i is the square root of -1.
  24. palmtree5

    palmtree5 Sunny Vacation Supporter! Moderator

    Never thought I'd see calculus references here...
  25. scary alien

    scary alien not really so scary Moderator

    I know, right?!

    ;) :p :) :D

Share This Page