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  • S Sean Cundiff

    Jeremy Falcon wrote:

    Given what you and Chris said, I suppose the idea I'm trying to understand then is why is Pi an irrational number? What makes it go on forever?

    Because pi <> P/Q ;P Seriously, if you can answer why some of the most important numbers known to man are irrational (e, pi, h_bar, etc) you will be a god among insects. -Sean ---- Shag a Lizard

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    Jeremy Falcon
    wrote on last edited by
    #9

    Sean Cundiff wrote:

    Seriously, if you can answer why some of the most important numbers known to man are irrational (e, pi, h_bar, etc) you will be a god among insects.

    It's going to drive me crazy if it never "clicks". Time for my medication now! Breathe. Breathe Jeremy! :-D Jeremy Falcon

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    • J Jeremy Falcon

      Sean Cundiff wrote:

      Seriously, if you can answer why some of the most important numbers known to man are irrational (e, pi, h_bar, etc) you will be a god among insects.

      It's going to drive me crazy if it never "clicks". Time for my medication now! Breathe. Breathe Jeremy! :-D Jeremy Falcon

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      Sean Cundiff
      wrote on last edited by
      #10

      Think of it this way: pi = circumference of a circle / diameter of the circle. There is no way to set the circumference to a rational quantity while at the same time keeping the diameter a rational quantity. pi = rational/irrational or irrational/rational. Why such a fundamental thing as a circle exhibits this quantity property is a matter of philosophical debate. -Sean ---- Shag a Lizard -- modified at 22:06 Thursday 16th March, 2006

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      • J Jeremy Falcon

        Sean Cundiff wrote:

        Seriously, if you can answer why some of the most important numbers known to man are irrational (e, pi, h_bar, etc) you will be a god among insects.

        It's going to drive me crazy if it never "clicks". Time for my medication now! Breathe. Breathe Jeremy! :-D Jeremy Falcon

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        Chris Maunder
        wrote on last edited by
        #11

        When the meds have kicked in take a look at transcendental numbers[^]. Pi's not only irrational, it's also transcendental. cheers, Chris Maunder

        CodeProject.com : C++ MVP

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        • J Jeremy Falcon

          Sean Cundiff wrote:

          Seriously, if you can answer why some of the most important numbers known to man are irrational (e, pi, h_bar, etc) you will be a god among insects.

          It's going to drive me crazy if it never "clicks". Time for my medication now! Breathe. Breathe Jeremy! :-D Jeremy Falcon

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          code frog 0
          wrote on last edited by
          #12

          Work the proof for PI you might find that is exactly what you need. http://en.wikipedia.org/wiki/Pi[^]

          A Plain English signature. Code-frog System Architects, Inc.

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          • J Jeremy Falcon

            Super Lloyd wrote:

            Could you explain your exact problem? That would help us give you a good solution!

            I did. I asked why is Pi infinite. I understand what you said, but that still doesn't address why it is like that - it just reaffirms it's infinite. I'm trying to really understand Pi outside a textbook definition I reckon. Jeremy Falcon

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            Super Lloyd
            wrote on last edited by
            #13

            it's not infinite, it's 3.14159265.... infinite is much bigger than that! ;P do you mean never repeat? 1st I believe you could have never repeating rationale (integer / integer) as well, this is simply an artefact of decimal notation. 2nd: yes PI is very special, it's a not even a real such as SQRT(2). Real number (as opposed to rational and integer) are solutino to polynomes equation (e.g. x^2 = 2) No Polynome with real parammters has PI has its solution. (same for 'e' (i.e. 2.7182818...)) they solve an other class of problem altogether...

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            • J Jeremy Falcon

              Super Lloyd wrote:

              Could you explain your exact problem? That would help us give you a good solution!

              I did. I asked why is Pi infinite. I understand what you said, but that still doesn't address why it is like that - it just reaffirms it's infinite. I'm trying to really understand Pi outside a textbook definition I reckon. Jeremy Falcon

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              Super Lloyd
              wrote on last edited by
              #14

              BTW, if PI repeated, it could expressed as a rational, hence it can't be!

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              • S Sean Cundiff

                Think of it this way: pi = circumference of a circle / diameter of the circle. There is no way to set the circumference to a rational quantity while at the same time keeping the diameter a rational quantity. pi = rational/irrational or irrational/rational. Why such a fundamental thing as a circle exhibits this quantity property is a matter of philosophical debate. -Sean ---- Shag a Lizard -- modified at 22:06 Thursday 16th March, 2006

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                Jeremy Falcon
                wrote on last edited by
                #15

                Sean Cundiff wrote:

                Why such a fundamental thing as a circle exhibits this quantity property is a matter of philosophical debate.

                You just beat me to my question. Jeremy Falcon

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                • C code frog 0

                  Work the proof for PI you might find that is exactly what you need. http://en.wikipedia.org/wiki/Pi[^]

                  A Plain English signature. Code-frog System Architects, Inc.

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                  Jeremy Falcon
                  wrote on last edited by
                  #16

                  It still didn't address the why. If it did, I didn't understand it. :) Jeremy Falcon

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                  • C Chris Maunder

                    When the meds have kicked in take a look at transcendental numbers[^]. Pi's not only irrational, it's also transcendental. cheers, Chris Maunder

                    CodeProject.com : C++ MVP

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                    Jeremy Falcon
                    wrote on last edited by
                    #17

                    Chris Maunder wrote:

                    Pi's not only irrational, it's also transcendental.

                    :doh: Back to the books for me. :laugh: Jeremy Falcon

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                    • S Super Lloyd

                      it's not infinite, it's 3.14159265.... infinite is much bigger than that! ;P do you mean never repeat? 1st I believe you could have never repeating rationale (integer / integer) as well, this is simply an artefact of decimal notation. 2nd: yes PI is very special, it's a not even a real such as SQRT(2). Real number (as opposed to rational and integer) are solutino to polynomes equation (e.g. x^2 = 2) No Polynome with real parammters has PI has its solution. (same for 'e' (i.e. 2.7182818...)) they solve an other class of problem altogether...

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                      Jeremy Falcon
                      wrote on last edited by
                      #18

                      Super Lloyd wrote:

                      do you mean never repeat?

                      I was under the impression it was infinite, just as 1/3 would also be. Jeremy Falcon

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                      • S Super Lloyd

                        it's not infinite, it's 3.14159265.... infinite is much bigger than that! ;P do you mean never repeat? 1st I believe you could have never repeating rationale (integer / integer) as well, this is simply an artefact of decimal notation. 2nd: yes PI is very special, it's a not even a real such as SQRT(2). Real number (as opposed to rational and integer) are solutino to polynomes equation (e.g. x^2 = 2) No Polynome with real parammters has PI has its solution. (same for 'e' (i.e. 2.7182818...)) they solve an other class of problem altogether...

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                        Vikram A Punathambekar
                        wrote on last edited by
                        #19

                        Super Lloyd wrote:

                        PI is very special, it's a not even a real such as SQRT(2).

                        What do you mean? :wtf: Of course PI is a real number! The definition of a real number is that it's square should be nonnegative. And PI * PI is nonnegative. Cheers, Vikram.


                        I don't know and you don't either. Militant Agnostic

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                        • V Vikram A Punathambekar

                          Super Lloyd wrote:

                          PI is very special, it's a not even a real such as SQRT(2).

                          What do you mean? :wtf: Of course PI is a real number! The definition of a real number is that it's square should be nonnegative. And PI * PI is nonnegative. Cheers, Vikram.


                          I don't know and you don't either. Militant Agnostic

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                          Super Lloyd
                          wrote on last edited by
                          #20

                          As Chris Munder said, it's a Transcendental number[^], much more uncommon than mere real number.

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                          • J Jeremy Falcon

                            It still didn't address the why. If it did, I didn't understand it. :) Jeremy Falcon

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                            code frog 0
                            wrote on last edited by
                            #21

                            Gosh you got me. I remember doing this in school and I remember using it with integrals and the special number e. Your question doesn't seem to have a conclusive answer from mathematics other than, "Most mathematicians agree that PI is infinite, irrational and transcendental and would be very surprised to learn it wasn't." I remember one form of something we did was that prove pi isn't infinite. So we tried picking a ratio of integers to prove that but the ratio went on forever and a proof was used to demonstrate that. I don't remember the specifics but anyway... Get yourself a couple hundred crays and work it out. I guess they have PI to trillions of non repeating decimals so you'd need a few crays for sure...:omg:

                            A Plain English signature. Code-frog System Architects, Inc.

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                            • J Jeremy Falcon

                              Sean Cundiff wrote:

                              All irrational numbers have the property that they are infinitely long, otherwise it would be possible to write them as P/Q and thus be a rational number.

                              Ok that makes sense. Given what you and Chris said, I suppose the idea I'm trying to understand then is why is Pi an irrational number? What makes it go on forever? And yeah, I'm trying to improve my math skills, so bear with me. :-O Jeremy Falcon

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                              Marc Clifton
                              wrote on last edited by
                              #22

                              Jeremy Falcon wrote:

                              What makes it go on forever?

                              It's a number that is computed by an infinite series of smaller and smaller parts. For example, look at this.[^] Besides a lot of complicated equations, there's this very simple one: pi/4 = 1 - 1/3 + 1/5 - 1/7 ... You can see how the series is infinite, but smaller and smaller. So that's what makes it go on forever, and the resulting number is irrational, as discussed in the previous posts. Marc Pensieve Functional Entanglement vs. Code Entanglement Static Classes Make For Rigid Architectures

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                              • J Jeremy Falcon

                                It still didn't address the why. If it did, I didn't understand it. :) Jeremy Falcon

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                                Chris Maunder
                                wrote on last edited by
                                #23

                                Change the question around. Instead of asking "why can't Pi be expressed as P/Q", ask yourself "Why should any random real number (ie not an integer, not a complex number) be lucky enough to be expressable as P/Q" To have a number be able to be expressed, exactly, as a ratio of two other numbers is pretty remarkable. cheers, Chris Maunder

                                CodeProject.com : C++ MVP

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                                • J Jeremy Falcon

                                  Super Lloyd wrote:

                                  do you mean never repeat?

                                  I was under the impression it was infinite, just as 1/3 would also be. Jeremy Falcon

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                                  Super Lloyd
                                  wrote on last edited by
                                  #24

                                  Ha.. but in that case it could be expressed as simple rational such as: big number divided by big power of ten. And why that couldn't be I hear you ask? 1st it would be funny that 10 would be a relevant number for a circle but why not.... Anyway, while I do not know the reason for that myself I could argue that this guy Ferdinand von Lindeman[^] proved PI was transcendental (no solution of any polynome with ration parameter), hence it obviously never repeat

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                                  • V Vikram A Punathambekar

                                    Super Lloyd wrote:

                                    PI is very special, it's a not even a real such as SQRT(2).

                                    What do you mean? :wtf: Of course PI is a real number! The definition of a real number is that it's square should be nonnegative. And PI * PI is nonnegative. Cheers, Vikram.


                                    I don't know and you don't either. Militant Agnostic

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                                    code frog 0
                                    wrote on last edited by
                                    #25

                                    Any number squared would be non-negative...:~

                                    A Plain English signature. Code-frog System Architects, Inc.

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                                    • M Marc Clifton

                                      Jeremy Falcon wrote:

                                      What makes it go on forever?

                                      It's a number that is computed by an infinite series of smaller and smaller parts. For example, look at this.[^] Besides a lot of complicated equations, there's this very simple one: pi/4 = 1 - 1/3 + 1/5 - 1/7 ... You can see how the series is infinite, but smaller and smaller. So that's what makes it go on forever, and the resulting number is irrational, as discussed in the previous posts. Marc Pensieve Functional Entanglement vs. Code Entanglement Static Classes Make For Rigid Architectures

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                                      Chris Maunder
                                      wrote on last edited by
                                      #26

                                      Marc Clifton wrote:

                                      So that's what makes it go on forever

                                      Actually not quite. Infinite series can easily add up to a rational number, or even an integer. 1/2 + 1/4 + 1/8 + ... = 1 cheers, Chris Maunder

                                      CodeProject.com : C++ MVP

                                      -- modified at 22:38 Thursday 16th March, 2006

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                                      • C Chris Maunder

                                        Marc Clifton wrote:

                                        So that's what makes it go on forever

                                        Actually not quite. Infinite series can easily add up to a rational number, or even an integer. 1/2 + 1/4 + 1/8 + ... = 1 cheers, Chris Maunder

                                        CodeProject.com : C++ MVP

                                        -- modified at 22:38 Thursday 16th March, 2006

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                                        Marc Clifton
                                        wrote on last edited by
                                        #27

                                        Chris Maunder wrote:

                                        Infinite series can easily add up to a rational number, or even an integer.

                                        Ah, good point. I better stick to programming. :) Marc Pensieve Functional Entanglement vs. Code Entanglement Static Classes Make For Rigid Architectures

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                                        • M Marc Clifton

                                          Jeremy Falcon wrote:

                                          What makes it go on forever?

                                          It's a number that is computed by an infinite series of smaller and smaller parts. For example, look at this.[^] Besides a lot of complicated equations, there's this very simple one: pi/4 = 1 - 1/3 + 1/5 - 1/7 ... You can see how the series is infinite, but smaller and smaller. So that's what makes it go on forever, and the resulting number is irrational, as discussed in the previous posts. Marc Pensieve Functional Entanglement vs. Code Entanglement Static Classes Make For Rigid Architectures

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                                          J Offline
                                          Jeremy Falcon
                                          wrote on last edited by
                                          #28

                                          Marc Clifton wrote:

                                          You can see how the series is infinite, but smaller and smaller.

                                          I got all of that stuff. But it doesn't explain why the series exist in the first place. Fortunately, I think I got enough info from the fine folks at CP to help me set out a course to improve my understanding on it. I'm just not there yet. :) Jeremy Falcon

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