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  3. 1 = 0

1 = 0

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  • D Dominic Burford

    x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

    "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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    mBuchwald
    wrote on last edited by
    #43

    This appears to work, but only because you are dividing by zero since (x-y) is, by definition of the first line, equal to zero.

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    • D Dominic Burford

      x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

      "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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      Dominic Amann
      wrote on last edited by
      #44

      huh? I don't think x = y implies x2 = xy. How did you get that?

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      • H HobbyProggy

        The only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

        Rules for the FOSW ![^]

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        willichan
        wrote on last edited by
        #45

        HobbyProggy wrote:

        because 1/3 is 0,333

        No. 1/3 does not equal 0.333. 1/3 is APPROXIMATELY 0.333. and 0.99999 is not technically 1. It is APPROXIMATELY 1 There is even a different symbol for it. 1/3≈0.333 (1/3 is approximately equal to 0.333) 0.99999≈1 (0.99999 is approximately equal to 1)

        Money makes the world go round ... but documentation moves the money.

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        • Sander RosselS Sander Rossel

          A high school teacher showed this to me some 10+ years back (feeling old now). All I can say is no.

          Visit my blog at Sander's bits - Writing the code you need. Or read my articles at my CodeProject profile.

          Simplicity is prerequisite for reliability. — Edsger W. Dijkstra

          Regards, Sander

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          James Curran
          wrote on last edited by
          #46

          Quote:

          A high school teacher showed this to me some 10+ years back (feeling old now).

          10+ years is making you feel old? I saw that in high school 35+ years old..... (*) Even then, was able to figure out the flaw.

          Truth, James

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          • D Dominic Burford

            x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

            "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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            Member_5893260
            wrote on last edited by
            #47

            As has been pointed out here, at some point you're dividing erroneously. But, you can prove that 0 = any number you want, using the derivation of differential calculus, as described here[^]: if you plug numbers into the equation at stage 3, you can "prove" pretty much whatever you want to prove. But of course, math is a language, not reality - and you can speak nonsense in any language.

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            • D Dominic Burford

              x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

              "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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              Member 11711973
              wrote on last edited by
              #48

              If 1 = 0, then 1 - 1 = 0 - 1, which means -1 = 0. Contradiction, so 1 = 0 can't be true.

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              • D Dominic Burford

                x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                charleslbryant
                wrote on last edited by
                #49

                This is a code site so I wanted to prove this with C# and it fell apart for me.

                [TestMethod]
                public void TestMethod1()
                {
                //x = y
                //Assuming y = 5.
                var y = 5;

                        var x = y;
                
                        //Then x2 = xy
                        Assert.AreEqual(x \* 2, x \* y); //Assert.AreEqual failed. Expected:<10>. Actual:<25>.
                    }
                
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                • D Dominic Burford

                  x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                  "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                  ClockMeister
                  wrote on last edited by
                  #50

                  Sorry, that doesn't work. x2 is NOT equal to xy. That's like saying 2x = x*y which is ONLY true if x and y are both 2. Cute, but does not float.

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                  • D Dominic Burford

                    x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                    "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                    Vachaun22
                    wrote on last edited by
                    #51

                    Well, the first problem with this is x = y then x2 = xy IFF x = y = 2 This was stated just above, but I didn't get that far when I was reading the comments...

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                    • H HobbyProggy

                      The only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

                      Rules for the FOSW ![^]

                      if(this.signature != "")
                      {
                      MessageBox.Show("This is my signature: " + Environment.NewLine + signature);
                      }
                      else
                      {
                      MessageBox.Show("404-Signature not found");
                      }

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                      jschell
                      wrote on last edited by
                      #52

                      HobbyProggy wrote:

                      because 1/3 is 0,333..

                      No it isn't. Mathematics defines and recognizes rational numbers. Mathematics defines and recognizes decimal numbers. They are two different things. Your equating them as the same does not remove certainly hundreds of years of mathematics and mathematicians that recognize and correctly differentiate the two. Certainly when I took mathematics courses that taught mathematics as it was implemented in computers they emphasized the assumptions and limitations of finite math. Actually understanding those assumptions and limitations makes the difference clear. Note clearly that in the above those were mathematics classes and not computer science classes. The difference is often where the former teaches the math and the later teaches how to use the computer. (Yes I took both.)

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                      • D Dominic Burford

                        x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                        "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                        Member 3934551
                        wrote on last edited by
                        #53

                        Seeing you're playing with polynomials there, aren't you? following the logics.. x = y x^2 = xy x^2-y^2 = xy-y^2 (x-y)(x+y) = (x-y)y x+y = y 2y = y however you draw the wrong conclusion here, go on like this: 2y-y = y-y y = 0

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                        • H HobbyProggy

                          The only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

                          Rules for the FOSW ![^]

                          if(this.signature != "")
                          {
                          MessageBox.Show("This is my signature: " + Environment.NewLine + signature);
                          }
                          else
                          {
                          MessageBox.Show("404-Signature not found");
                          }

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                          obermd
                          wrote on last edited by
                          #54

                          Actually 1.0 = 0.9999... I did the derivation of this proof as an exercise in a algebra class back in the early 80s.

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                          • D Dominic Burford

                            x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                            "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                            prakhar19
                            wrote on last edited by
                            #55

                            You can't divide any number with 0. (x-y=0) Divide by 0 is infinity, and infinity can't be equated.

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                            • H HobbyProggy

                              The only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

                              Rules for the FOSW ![^]

                              if(this.signature != "")
                              {
                              MessageBox.Show("This is my signature: " + Environment.NewLine + signature);
                              }
                              else
                              {
                              MessageBox.Show("404-Signature not found");
                              }

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                              maze3
                              wrote on last edited by
                              #56

                              1 === 3/3 === X/X The thing is base 10 decimal (0.333) does not have a correct way to represent 3/3, except putting bar above the value that repeats infinitely _ 0.333

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                              • H HobbyProggy

                                The only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

                                Rules for the FOSW ![^]

                                if(this.signature != "")
                                {
                                MessageBox.Show("This is my signature: " + Environment.NewLine + signature);
                                }
                                else
                                {
                                MessageBox.Show("404-Signature not found");
                                }

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                                Member 12023988
                                wrote on last edited by
                                #57

                                Quote:

                                Go to ParentThe only thing i can agree with is that 1 != 3/3 (at least not exactly) because 1/3 is 0,333... and multiplied with 3 it is just 0,99999.... which is technically 1 but not 100%

                                This is nonsense ... .999... is exactly equal to 1, just as .333... is exactly equal to 1/3.

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                                • D Dominic Amann

                                  huh? I don't think x = y implies x2 = xy. How did you get that?

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                                  Member 12023988
                                  wrote on last edited by
                                  #58

                                  "x2" is supposed to mean x squared.

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                                  • C ClockMeister

                                    Sorry, that doesn't work. x2 is NOT equal to xy. That's like saying 2x = x*y which is ONLY true if x and y are both 2. Cute, but does not float.

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                                    Member 12023988
                                    wrote on last edited by
                                    #59

                                    Why do so many people here fail to grasp the obvious, that "x2" is meant to represent x squared? It's almost as if the CP community isn't very high quality.

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                                    • D Dominic Burford

                                      x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                                      "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                                      dpminusa
                                      wrote on last edited by
                                      #60

                                      x-y=0. You are dividing by 0. Therefore your theorem falls apart at that point. Nice try.

                                      "Courtesy is the product of a mature, disciplined mind ... ridicule is lack of the same - DPM"

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                                      • D Dominic Burford

                                        x = y. Then x2 = xy. Subtract the same thing from both sides: x2 - y2 = xy - y2. Dividing by (x-y), obtain x + y = y. Since x = y, we see that 2 y = y. Thus 2 = 1, since we started with y nonzero. Subtracting 1 from both sides, 1 = 0. :wtf:

                                        "There are two ways of constructing a software design: One way is to make it so simple that there are obviously no deficiencies, and the other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult." - C.A.R. Hoare Home | LinkedIn | Google+ | Twitter

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                                        RogerStef
                                        wrote on last edited by
                                        #61

                                        "x2 = xy" This is VERY wrong, I guess? :^)

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                                        • H HobbyProggy

                                          Allright, tell that the next flightcomputer that breakes down because he multiplied 0,333 and didn't get to 1 ;)

                                          Rules for the FOSW ![^]

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                                          yiangos
                                          wrote on last edited by
                                          #62

                                          Well... 0.999... is 0+(9/10) + (9/100) + (9/1000) +... which is 0+9*((1/10)+(1/100)+(1/1000)+...) which is 9* (sum(1/10^n)) where the sum runs over n for n=1 to infinity. Now for the same sum, if n ran from 0 to infinity, there is a convenient formula, that says it is (I'll mark this with a capital S to distinguish it from the one we're trying to calculate): Sum(1/10^n)=1+1/10+1/100+...=1/(1-(1/10))=1/(9/10)=10/9 therefore the sum we want is 1/10+1/100+...=(10/9)-1=1/9 therefore 0.999...=9*(1/9)=1 So it's math. On the other hand, computer calculated numbers are approximations, and in the binary system at that, and this is why you get all those rounding errors. But I get the feeling you already know all this, and that you are just toying with us obsessive compulsive types.

                                          Φευ! Εδόμεθα υπό ρηννοσχήμων λύκων! (Alas! We're devoured by lamb-guised wolves!)

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