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Infinity * infinity

  1. Feb 12, 2005 #1
    x + x = 2x
    infinity + infinity = 2 infinity (or) infinity
    infinity * infinity = square of infinity (or) infinity
    :tongue: :devil: :blushing: :approve:
  2. jcsd
  3. Feb 12, 2005 #2


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    0 + 0 = 0.

    Absolute nothingness + This thread = ....
  4. Feb 26, 2005 #3
    have though alot about zeros and infinities... not a very high level maybe, but hey, I'm just 17....:)

    about infinity + infinity = 2*infinity ?

    see it like this.. in a 1cm line, there are infinite many points ...
    in a 2cm line there is also infinite many points....

    so if you have 2 1cm lines they will have infinite+infinite points, which is also infinite as the 2cm line also had infinite many points...

    hope I wasnt confusing.....

    and infinity * infinity = square of infinity ?

    you have a line of any length with infinite many points.. say 1cm again
    if you have four lines forming a square with, then, the area of 1cm^2 you will have infinite many points in the area......

    so the lines of infinite many points, make a square with infinte * infinte many points in the square, which as said earlier his infinite..
    so infinity * infinity = infinity..

    I have some problem with infinity - infinity though...

    I have infiinity.... I add another infinity and get.. infinity.. so If i subtract infinity now, I should get ack to my original number or?

    so x+x-x = x or??
    in case of infinty we get
    x+x-x != x

    weird.. but however.. its intresting stuf... have some other stuff i have thought of.. will post it another time.......
  5. Feb 26, 2005 #4
    since infinity is a proper subset of infinity+infinity, they can be put in one-to-one correspondence to eachother, and are then the same "degree" of infinity, am I right?
    Last edited: Feb 26, 2005
  6. Feb 26, 2005 #5


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    Head... hurting... :cry:

    None of this makes any sense until you adopt some definitions... and then once you have, it's clear how things work.
  7. Feb 26, 2005 #6
    Infinity is not a number, it is a mathematical concept. The reason it isn't a number is because for ever number at 'infinity' there is always a number that is greater than it. It doesn't make very much sense to use the concept of infinity as a mathematical operator.

    Limits are the best way to show this correlation. If something is unbounded then it is useless to try to find a maximum number for Infinity.
  8. Feb 26, 2005 #7


    x=1 thus 1=.99999999..............

  9. Feb 26, 2005 #8
    also how about this one:
    construct a right triangle, say a triangle with sides=1 and with hypotenuse sqrt(2). obviously sqrt(2)>1, how then can all the points on the side that has length of sqrt(2) be matched to all the points on the line that has length 1 like shown in the picture? this problem mystified Leibniz

    Attached Files:

  10. Feb 26, 2005 #9
    sorry, gravenewworld bu t i didnt umderstand......
  11. Feb 26, 2005 #10
    I believe he tried to illustrate that a line twice as long can be projected down on the first line as if two sides of a triangle, and you can match up each point on one line to each one on the other... therefore, they must have equal number of points?
  12. Feb 26, 2005 #11
    Precisely kerbox
  13. Feb 27, 2005 #12


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    [tex]\mathbb{Z} \subset \mathbb{R} [/tex], no ?
  14. Feb 27, 2005 #13
    2=1 ????
    -1=0 ????

    How about them mathimatics!! :approve:
  15. Feb 27, 2005 #14

    sorry to ruin your fun but your example doesnt work.. :biggrin: :tongue:

    2x=x is ONLY true for 0 and infinity...
    so when you have 2x=x and divide by x to get 2=1,
    you actually divide by 0 or infinity. And as divison by 0 and infinity is undefined your conclusion is invalid...:)

    just rememebered a quote by J.Baylock....
    "If you want somone to hate you, explain to them, logically and politely, why they are wrong"

    a funny thing of division of 0's can be demonstrated in this way (thought it myself, but someone else may have done it)

    divide by 0 at both sides and you get

    so is 0/0 equal to 0??? :grumpy:

    nonono :tongue:

    divide by 0 at both sides and you get

    divide by 0 at both sides and you get

    divide by 0 at both sides and you get

    can cnotinue as long as I want... (or maybe not til infinity..) :biggrin:
  16. Feb 28, 2005 #15
    I was refering to this... They give nonsence I give nonsence! :smile:
  17. Mar 13, 2005 #16
    I prefer to think of it like this:

    ax=x => a=1 or x=0 or x=infinity.

    so 2x=x => a=2 => x=0 or x=infinity.
  18. Mar 13, 2005 #17


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    However, there is no number called "infinity", so "x = 0 or x = infinity" is equivalent to "x = 0"!
  19. Mar 20, 2005 #18

    Infinity is not a number.

  20. Mar 20, 2005 #19
    Does x always have to be a number in maths?
  21. Mar 20, 2005 #20


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    Dearly Missed

    You are using operations like multiplication and addition which are only defined on a set of numbers.
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