Mathematical Theory (controversy!)

  • Getting back onto the theme of the original post.

    If 0.999 recurring = 1, then does 0.00...1 = 0?

    The issue I have with 0.999 recurring = 1 is that a statement testing for it wouldn't work ie

    if 0.999999 rec. = 1 then true else false

    this would always return false.

    Also 0 != Null?

  • paul.phillips (9/16/2011)


    Getting back onto the theme of the original post.

    If 0.999 recurring = 1, then does 0.00...1 = 0?

    The issue I have with 0.999 recurring = 1 is that a statement testing for it wouldn't work ie

    if 0.999999 rec. = 1 then true else false

    this would always return false.

    Also 0 != Null?

    Yes, 0.000.......1 = 0, if you mean, mathematically, the limit of 1/x as x approaches infinity. You could think of it as 1 - 0.9999999..., which, by prior discussion here, is the same as 1 - 1 = 0.

    The reason you can't have a working statement to test it is because there is no computer language I know of that allows you to store an infinite number of zeros. (Maybe there are languages that mathematicians use that store a representation of infinite series, but you can't actually store an infinite number of digits in a computer, not even with the low price of disks these days :-D)

    In T-SQL, for example, REAL and FLOAT data types have limited precision, and any efforts to perform computations that transcend those limits lead to errors.

    I won an argument in high school about this: some smart alec "proved" that (1/9)^20 = 0 b/c if you used a calculator to divide 1 by 9, then by 9, etc. 20 times, you got 0. My reply: well then, if you take that result and multiply it by 9 20 times do you get your original starting value of 1? No? Then your answer was truncated by round-off error.

    It's good that you "have a problem with this", b/c if you try doing it with a computer, you will have problems! The computer only approximates reality. Three children dividing a pie in thirds have performed a mathematical computation that cannot be stored in a Cray.

    Rich

  • rmechaber (9/16/2011)


    It's good that you "have a problem with this", b/c if you try doing it with a computer, you will have problems! The computer only approximates reality. Three children dividing a pie in thirds have performed a mathematical computation that cannot be stored in a Cray.

    Rich

    Although that would never happen. The biggest kid would get more pie.

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  • jcrawf02 (9/16/2011)


    rmechaber (9/16/2011)


    It's good that you "have a problem with this", b/c if you try doing it with a computer, you will have problems! The computer only approximates reality. Three children dividing a pie in thirds have performed a mathematical computation that cannot be stored in a Cray.

    Rich

    Although that would never happen. The biggest kid would get more pie.

    What? Didn't you ever play the "one kid cuts, the other one chooses the piece" game? You just need a bigger big kid (a.k.a. parent) to enforce the rules of the game.

    Rich

  • rmechaber (9/16/2011)


    jcrawf02 (9/16/2011)


    rmechaber (9/16/2011)


    It's good that you "have a problem with this", b/c if you try doing it with a computer, you will have problems! The computer only approximates reality. Three children dividing a pie in thirds have performed a mathematical computation that cannot be stored in a Cray.

    Rich

    Although that would never happen. The biggest kid would get more pie.

    What? Didn't you ever play the "one kid cuts, the other one chooses the piece" game? You just need a bigger big kid (a.k.a. parent) to enforce the rules of the game.

    Rich

    That's cheating!! :w00t:


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  • In our house, it was more of a "dad cuts into sixteen equal pieces, kids get a piece each, next morning the rest have mysteriously disappeared" kinda game. For some reason he made us call him "tax man"...

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  • jcrawf02 (9/16/2011)


    In our house, it was more of a "dad cuts into sixteen equal pieces, kids get a piece each, next morning the rest have mysteriously disappeared" kinda game. For some reason he made us call him "tax man"...

    Cue The Beatles ...

    Now I'll have that song stuck in my head the rest of the day!

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  • paul.phillips (9/16/2011)


    Getting back onto the theme of the original post.

    If 0.999 recurring = 1, then does 0.00...1 = 0?

    The issue I have with 0.999 recurring = 1 is that a statement testing for it wouldn't work ie

    if 0.999999 rec. = 1 then true else false

    this would always return false.

    Also 0 != Null?

    Look up "null" in a dictionary. You'll find, "mathematics relating to zero: relating to or equal to zero". So, it depends on which definition of "null" you mean.

    And, on the test-by-code of .9... = 1, try it in SQL Server and you'll find that 1 != 1 because of a rounding error.

    SELECT 1.0/3.0*3.0;

    Gets 0.9999990 on my machine. The obvious mathematical answer is 1.0, but it doesn't short-circuit the math and realize that. It's not even doing .9-repeats, it puts a zero at the end, in the 7th decimal place, which is just plain wrong.

    - Gus "GSquared", RSVP, OODA, MAP, NMVP, FAQ, SAT, SQL, DNA, RNA, UOI, IOU, AM, PM, AD, BC, BCE, USA, UN, CF, ROFL, LOL, ETC
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  • GSquared (9/16/2011)


    Look up "null" in a dictionary. You'll find, "mathematics relating to zero: relating to or equal to zero". So, it depends on which definition of "null" you mean.

    You owned that word!

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