off topic but please forgive me me and answer
in [Python]
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From: Patrick Maupin on 3 Apr 2010 11:49 On Apr 3, 8:00 am, superpollo <ute...(a)esempio.net> wrote: > > sorry if I misunderstood. > > no no you understood prfectly *but* the thing is i am a regular in an > italian language math ng which is haunted by a crackpot who insists that > 1/2 * 1/2 cannot be 1/4, "because multiplication means getting bigger", > so i took a semi-serious stance and made a few posts as a statistical > tentative to "convince" said crackpot that the world is not going crazy > (but maybe he is) If I read correctly (using my non-existent Italian, and heavily relying on my tiny bit of Spanish and a lot of google translate), it appears that you are what I would call a high-school math/science teacher, who takes students to competitions? Regards, Pat
From: superpollo on 3 Apr 2010 11:56 Patrick Maupin ha scritto: > On Apr 3, 8:00 am, superpollo <ute...(a)esempio.net> wrote: >>> sorry if I misunderstood. >> no no you understood prfectly *but* the thing is i am a regular in an >> italian language math ng which is haunted by a crackpot who insists that >> 1/2 * 1/2 cannot be 1/4, "because multiplication means getting bigger", >> so i took a semi-serious stance and made a few posts as a statistical >> tentative to "convince" said crackpot that the world is not going crazy >> (but maybe he is) > > If I read correctly (using my non-existent Italian, and heavily > relying on my tiny bit of Spanish and a lot of google translate), it > appears that you are what I would call a high-school math/science > teacher, who takes students to competitions? right -- almost! i don't take them to competitions (i am not an official trainer) but sometimes give some general advice to students who would be inclined to compete, if they ask me. bye
From: Martin P. Hellwig on 3 Apr 2010 11:57 On 04/03/10 16:17, Steven D'Aprano wrote: > On Sat, 03 Apr 2010 15:43:41 +0100, Martin P. Hellwig wrote: > >> I am replying to this post not because I disagree but because it >> postalogically fits the best (I am by no means an expert either). >> >> IMHO, the crackpot in this regard is actually partially right, >> multiplication does mean that the number must get bigger, however for >> fractions you multiply four numbers, two numerators and two >> denominators. The resulting numerator and denominator by this >> multiplication get indeed bigger. > > But you're not multiplying four numbers, you're multiplying two numbers. > One-half is not "two numbers", that would be a tuple or a list or > possibly a coordinate pair. One-half is a single number, the number which > if you double it gives one. > I disagree with you there, but I only disagree with you on the definition of the syntax, not with the logic nor the explanation. I am not going to argue about syntax, since I don't think I would make a great argument (being the devil's advocate) and also because I believe when argued correctly, agreeing on disagreement of syntax allows even the greatest untruth be true and false at the same time. Excuse me please I need to feed Schroedinger's cat :-) -- mph
From: Mensanator on 3 Apr 2010 12:35 On Apr 3, 10:17 am, Steven D'Aprano <st...(a)REMOVE-THIS- cybersource.com.au> wrote: > On Sat, 03 Apr 2010 15:43:41 +0100, Martin P. Hellwig wrote: > > I am replying to this post not because I disagree but because it > > postalogically fits the best (I am by no means an expert either). > > > IMHO, the crackpot in this regard is actually partially right, > > multiplication does mean that the number must get bigger, however for > > fractions you multiply four numbers, two numerators and two > > denominators. The resulting numerator and denominator by this > > multiplication get indeed bigger. > > But you're not multiplying four numbers, You are if you're using Rationals. > you're multiplying two numbers. Because they're expressed as Decimals. > One-half is not "two numbers", Sometimes it is. > that would be a tuple Like this? >>> gmpy.mpq('0.5') mpq(1,2) > or a list or > possibly a coordinate pair. One-half is a single number, When dealing with crackpots, it does not help to use the wrong arguments. When multiplying gmpy.mpq(2,3) by gmpy.mpq(2,3), the numerator and denominator have both indeed gotten bigger. The trick is that when combined, the overall result is smaller. > the number which > if you double it gives one. > > Fortunately multiplication is consistent. Multiplying the two numbers 0.5 > and 0.5 is exactly the same as multiplying 1*1 and 2*2 then dividing to > get a single number. It's not the same as multiplying 1*1 and 2*2 to get > two numbers, 1 and 4. > > You say that multiplication means that the number "must get bigger". Yes, not in every case, but in many cases it does. You need to point out that it is wrong EVEN IN THE CASES WHERE IT'S TRUE. It is a Non Sequitur - it does not follow that a number must be bigger if the numerator and denominator have each gotten larger. > > 5*1 = 5 > 5*0 = 0 > 5*-2 = -10 > > I hope you won't try to argue that 5, 0 and -10 are all bigger than 5. Yes, but these special cases don't help. It needs to be pointed out that the argument is wrong even in cases like 2/3 * 2/3. > > There really is no point trying to dignify superpollo's friend's > assertion on the basis of some technicality. His argument is no different > from the argument that says that pythons are snakes, and therefore python > can't be a programming language and this newsgroup can't possibly exist. > Words can have multiple meanings, and meanings can shift. Multiply may be > derived from a word which, once upon a time, meant to get bigger, but > that's not what multiply means. I don't like to dismiss somebody I've > never met, but on the basis of what superpollo says, yes, he's a crackpot.. > > Either that or about age four. When I was four I strongly believed that > "one hundred" and "a hundred" were different numbers. I argued (not very > convincingly, but with great vehemence) to my teacher and my parents that > you counted up to ninety-nine, then a hundred, a hundred and one, a > hundred and two, ... a hundred and ninety-nine, *one* hundred. > > -- > Steven
From: Emile van Sebille on 3 Apr 2010 12:59
On 4/3/2010 8:46 AM Patrick Maupin said... > On Apr 3, 9:43 am, "Martin P. Hellwig"> IMHO, the crackpot in this > regard is actually partially right, >> multiplication does mean that the number must get bigger, however for >> fractions you multiply four numbers, two numerators and two >> denominators. The resulting numerator and denominator by this >> multiplication get indeed bigger. > > That argument is great! Just make sure that you've managed to leave > before the class has to learn about irrational numbers that don't > *have* numerators and denominators ;-) Ahh, but no ones arguing that irrational numbers don't get bigger -- even before you multiply them! Emile |