Members cmercein8 Posted October 10, 2009 Author Members Share Posted October 10, 2009 'nother classic version of the "2=1" with division by zero a = 2 a^2 = 2a a^2 - 4 = 2a-4 (a-2)(a+2) = 2(a-2) (divide both side with (a-2) ) a+2 = 2 2+2 = 2 4=2 2=1 Thank you dreamspace. Quote Link to comment Share on other sites More sharing options...
Members KovachianOne Posted October 10, 2009 Members Share Posted October 10, 2009 'nother classic version of the "2=1" with division by zero a = 2 a^2 = 2a irrelevant from here on due to error in step 2 If a = 2 then a^2 = 2^2 = 4, not 2a. Where the hell do you stoners come up with this? Please stay as far away from college as humanly possible. Quote Link to comment Share on other sites More sharing options...
Members dreamspace Posted October 10, 2009 Members Share Posted October 10, 2009 If a = 2 then a^2 = 4, not 2a. Where the hell do you stoners come up with this? Please stay as far away from college as humanly possible.you multiply both sides with a, you don't square both sides. and the post was to show that 2!=1, since you divide by zero when dividing (a-2) from both sides) Quote Link to comment Share on other sites More sharing options...
Members teemuk Posted October 10, 2009 Members Share Posted October 10, 2009 Quote Link to comment Share on other sites More sharing options...
Members KovachianOne Posted October 10, 2009 Members Share Posted October 10, 2009 you multiply both sides with a, you don't square both sides. and the post was to show that 2!=1, since you divide by zero when dividing (a-2) from both sides) That still comes out to 4 a = 2 a x a = 2 x a a still = 2 so 2a = 4 There's no getting around it buddy, sorry. And the rest of your math is still wrong. Quote Link to comment Share on other sites More sharing options...
Members dreamspace Posted October 10, 2009 Members Share Posted October 10, 2009 okay then, set the equation to a = b, instead of a = 2. The whole point was to show that the OP is wrong since his proof is invalid Quote Link to comment Share on other sites More sharing options...
Members Uncle_Milton Posted October 10, 2009 Members Share Posted October 10, 2009 Quality vs. Quantity Quote Link to comment Share on other sites More sharing options...
Members cmercein8 Posted October 10, 2009 Author Members Share Posted October 10, 2009 This whole thread is screwed. I'm gunna go play guitar. Quote Link to comment Share on other sites More sharing options...
Members dreamspace Posted October 10, 2009 Members Share Posted October 10, 2009 There's a whole bunch of examples, pick and choose http://en.wikipedia.org/wiki/Invalid_proof Quote Link to comment Share on other sites More sharing options...
Members Rogueleader Posted October 10, 2009 Members Share Posted October 10, 2009 That is just a stupid mathematical parlour trick more often used in philosophy than in any real math.Anything divided by zero is undefined (older mathematical texts sometimes say infinite but that has grown unpopular over the past 30 years).That is just a fancy way of saying your "proof" is incorrect. Quote Link to comment Share on other sites More sharing options...
Members Fuelish Posted October 10, 2009 Members Share Posted October 10, 2009 To quote Laurie Anderson .... "Let x = x " ...it's big science, ya know Quote Link to comment Share on other sites More sharing options...
Members Say Ocean Posted October 10, 2009 Members Share Posted October 10, 2009 That is just a stupid mathematical parlour trick more often used in philosophy than in any real math. Anything divided by zero is undefined (older mathematical texts sometimes say infinite but that has grown unpopular over the past 30 years). That is just a fancy way of saying your "proof" is incorrect. Yeah. Numbers are numbers... they relate to things in the real world but they and an intangible idea, and that's why there are rules like "you can't divide by zero" to ensure that algebra and such stays relevant to real applications. Otherwise you could make up whatever rules you want, but what's the point of that Quote Link to comment Share on other sites More sharing options...
Members LetsJet Posted October 10, 2009 Members Share Posted October 10, 2009 Now, it can be argued that 1=2. 0 x 1 = 0 0 x 2 = 0 So than this must be true: 0 x 1 = 0 x 2 Similarly: 0/0 x 1 = 0/0 x 2 Simplified, 1 = 2 By this logic every number equals every number..... 0 x 5 = 0 0 x 7 = 0 So than this must be true: 0 x 5 = 0 x 7 Similarly: 0/0 x 5 = 0/0 x 7 Simplified, 5 = 7 So I'll give you 1 dollar and you can give me a thousand and we'll call it even. Quote Link to comment Share on other sites More sharing options...
Members KovachianOne Posted October 10, 2009 Members Share Posted October 10, 2009 Besides, if you want to place a zero denominator on one side, you must place the entire side over zero, not just one number or the other. Then do the same to the other side of course (as in, the entire side). 0 x 1 = 0 x 2 so 0/0 x 1 = 0/0 x 2? Nope. This is how it goes: (0 x 1)/0 = (0 x 2)/0 Both sides equal 0 and thus, 0 = 0, not 1 = 2. And technically speaking, division by zero is possible but ONLY when the numerator is zero or at least comes out to zero. Quote Link to comment Share on other sites More sharing options...
Members Marshredder Posted October 10, 2009 Members Share Posted October 10, 2009 3/2 is 1. Not 1.5, but 1. This is what I was actually taught by one of my maths teachers, who is a Dr of Particle Physics, you even get taught his theories if you do a doctorate in Physics, but yeah, 3/2 is 1, because you always give the answer to the same amount of decimal places.hmm. Quote Link to comment Share on other sites More sharing options...
Members cmercein8 Posted October 10, 2009 Author Members Share Posted October 10, 2009 So I'll give you 1 dollar and you can give me a thousand and we'll call it even. Too bad my thousand dollars also equals -2000 dollars, so you would then owe me two thousand. Quote Link to comment Share on other sites More sharing options...
Members Say Ocean Posted October 10, 2009 Members Share Posted October 10, 2009 3/2 is 1. Not 1.5, but 1. This is what I was actually taught by one of my maths teachers, who is a Dr of Particle Physics, you even get taught his theories if you do a doctorate in Physics, but yeah, 3/2 is 1, because you always give the answer to the same amount of decimal places. hmm. You mean significant figures? Quote Link to comment Share on other sites More sharing options...
Members Marshredder Posted October 10, 2009 Members Share Posted October 10, 2009 You mean significant figures? I thought I would simplify it for the HCAF Dummies Quote Link to comment Share on other sites More sharing options...
Members -todgemistro- Posted October 10, 2009 Members Share Posted October 10, 2009 How is 3/2 anything other than 1.5? It makes no sense to me Quote Link to comment Share on other sites More sharing options...
Members cmercein8 Posted October 10, 2009 Author Members Share Posted October 10, 2009 How is 3/2 anything other than 1.5? It makes no sense to me Quote Link to comment Share on other sites More sharing options...
Members guitarbilly74 Posted October 10, 2009 Members Share Posted October 10, 2009 because you always give the answer to the same amount of decimal places. Quote Link to comment Share on other sites More sharing options...
Members -todgemistro- Posted October 10, 2009 Members Share Posted October 10, 2009 I dont understand maths and that quote means nothing to me half of 3 is 1.5 to my simple mind Dont know how I got a B at GCSE. Quote Link to comment Share on other sites More sharing options...
Members LetsJet Posted October 10, 2009 Members Share Posted October 10, 2009 Too bad my thousand dollars also equals -2000 dollars, so you would then owe me two thousand.Tell you what, I'll take your thousand and I'll see what it equals. Quote Link to comment Share on other sites More sharing options...
Members pioneerprogress Posted October 10, 2009 Members Share Posted October 10, 2009 Quote Link to comment Share on other sites More sharing options...
Members JBecker Posted October 10, 2009 Members Share Posted October 10, 2009 1) .999... is =1, that proof is not invalid. 2) You cannot divide by 0 ever, and multiplying by 0 removes all information so it cannot be used in these proofs. This is why I shouldn't argue with people on the internet, because even fundamental math proofs that require the most basic logic skills taught in high school are lost on the internet. Quote Link to comment Share on other sites More sharing options...
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