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X/0 = x

  1. Jan 15, 2004 #1
    Lets try arguing in not mathematical terms but logical reasoning. if a number x is divided by any number n, it means giving every individual n a single part from x... if our number is zero how are we going to divide x to zero individuals...? we have a x objects to be divided among no one... either the number stays as it is or a the number is gone. but the number cannot be gone because it was distributed to no one.. how is this???
  2. jcsd
  3. Jan 15, 2004 #2


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    (1) It is not a good idea to use mathematical notation for something that is not given in "mathematical terms".
    (2) Your logic is wrong.
    (3) You definition of division is wrong.
  4. Jan 15, 2004 #3
    "..., with all parts of equal magnitude..." needs to be added to your specification.

    Zero parts means no parts at all. But they must finally add up to 1. If the total magnitude of parts is less than 1, then the parts must be too small.

    For example, if you guess that 2 is 20/5, then five 2s comprise only 10. That's too small, so 20/5 must be larger than 2. Likewise, five 3s is smaller than 20, so 20/5 must be larger than 3. But five 5s is larger than 20, so 5 is too big for 20/5. It turns out that five 4s is just right, total magnitude 20. So 4 is 20/5.

    Back to 1/0:
    If you guess 1,000,000, then NO 1,000,000s is 0, and less than 1, so 1,000,000 is too small for the magnitude of a part. You can easily see that any whole number x is just too small to make NO xs equal to 1. One might be tempted to try a surpassing infinite magnitude. But "NONE of those" still adds up to 0, not 1. So you are left with no viable answer.

    In brief: for any magnitude x, x*0 = 0, so 1/0 has no viable solution.
  5. Jan 15, 2004 #4
    going back to what you have stated that

    .......if a number x is divided by any number n, it means giving every individual n a single part from x....

    This simply means that each person from the n people would be receiving x/n parts of the x (that is if the number x is to be divided equally among the n people). But did you give any part of the x to any one? the answer is no. so the answer is still 0. got my point?
  6. Jan 15, 2004 #5

    Mathematics says this wrong because it defined something that makes it wrong. mathematics defined everything, but logic can never be defined. its our mind that makes logic!
  7. Jan 16, 2004 #6


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    I would recommend that you actually study logic before you make such sweeping statements.
  8. Jan 18, 2004 #7
    better try to understand the logic behind the problem itself. however, it is still MATHEMATICAL in nature ( the way you would be presenting the solution to the problem is mathematical in nature)
    the other explanation (still using mathematical reasoning) is by {cross multiplication} however this does not make any sense at all.

  9. Jan 21, 2004 #8
    thanks for the advice... id better study more!!
  10. Jan 26, 2004 #9
    The problem is that x/0 doesn't equal anything it is undefined.
  11. Jan 26, 2004 #10
    The problem is that x/0 doesn't equal anything it is undefined.

    you better try to explain more what you have written. it is very confusing.

    or do you mean "The problem is that x/0 doesn't equal anything. it is undefined. ????
  12. Feb 1, 2004 #11
    What do you mean with "equal anything"?
  13. Feb 1, 2004 #12
    you better ask ruud about it. just an empahasis on the sentence he/she had written specially on the period (.)
  14. Feb 2, 2004 #13
    I think one of the main problems with this statement is that it does not make sense to divide something among zero people while looking for the amount each person received. If you have a cake and nobody wants it, then yes the cake is still there, but this is not the same as dividing the cake among zero people then finding how much cake each person has because there are no people to receive the cake. You should not be looking for the remainder of the cake but the amount of cake each person received. And as I have hopefully shown this causes the problem to fall apart.
  15. Apr 8, 2010 #14
    i agree with the second comment on this thread, the problem is in the definition of division. devision is simply the inverse operation of multiplication. if we ask "how many will we have, if we have n, m number of times?" we have n*m=nm. if we do the inverse of this and as "how many will times can nm be divided into groups of n?" which will translate nm/n=m.

    all this to say:

    if we have x zero times, we have nothing, which we write x*0=0. if we ask how many times we can divide x into groups of zero (x/0), it just doesn't make since. This is why it is "undefined".

    math commandment IV. Thou shalt not divide by zero!
  16. Apr 9, 2010 #15


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    math Ecclesiastes III. Sometime you can divide by 0. :tongue:

    In the projective reals, or the trivial field, for example.
  17. Apr 22, 2010 #16
    Yes. Things always look different when you see things in terms of circles rather than (extended) lines.
    Last edited: Apr 22, 2010
  18. Apr 23, 2010 #17


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    luther_paul, your logical example only seems to apply for all natural numbers. This is the example given to children in primary school so they can understand division.

    Division can be extended upon, and it's no surprised your example breaks down. Unless you believe otherwise, please explain to me using the same logic how to divide by 1.4, or even -2.
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