Hi :) I went a little crazy last night. Tooo little chocolate in last few days and then had so much i passed out. Sorry about posts, especially to Regina.
More at bottom to answer Steve Regards from Tom :) ----- Original Message ---- > From: Steve Edmonds <steve.edmo...@ptglobal.com> > To: documentation@global.libreoffice.org > Sent: Sat, 11 June, 2011 5:29:51 > Subject: Re: [libreoffice-documentation] Re: Collecting small things in the >Wiki > > > > On 11/06/11 11:29, Tom Davies wrote: > > Hi :) > > > > Regina, this is not a criticism of you but just some of my anger at the >world > > > that gave me a fairly decent education in sciences and maths and made me > > practically unemployable as a result. > > > > > > Ok, again > > > > -3 x -3 = 9 > > > > I think people tend to expect the - to make the result -9. Perhaps they >expect > > > the result to be the same as -(3^2) which is a completely different thing. > > > > Again this is more about people lack of maths understanding than about > > spreadsheets. An evening course or on-line course about maths is the >answer, > > > not documentation for a spreadsheet program. > > > > > > In the bug-report the first comment complains that spreadsheet programs >stick to > > > > > internationally agreed maths standard for the order in which to apply >functions, > > > > > Bodmas (stands for "Brackets, of/division, multiplication, add, > > subtract"). > > > Choosing a non-standards order makes higher functions exponentially >difficult or > > > > > even impossible. Before the 0 was borrowed from Arabic notation simple > > multiplication and division was only possible by people with a university >degree > > > > > level of maths skills. Choosing to go against Bodmas would be similarly > > catastrophic. > > > > Business users like to left align numbers which makes simple addition more > > difficult at a glance, for example > > > > £34 > > £300 > > ====== > > £640 ?!!? > > > > Maths people and accountants tend to shudder at left aligned numbers, or >realise > > > > > they are likely to make a lot of cash from these people. A > > right-justified >list > > > > > makes it much more obvious > > > > £34 > > £300 > > ===== > > £334 in a much more obvious way. Ok, its a stupid example with only 2 >numbers > > > in the list but imagine with a LOT more numbers in the list, say 20 to 30 >per > > > page. > > > > > > Back to the expected result of -9. What is the square root? -3 x 3 is not > > really right. In fact we are now getting towards 2 dimensional numbers >such as > > > "imaginary numbers" and perhaps even getting close to chaos theory and >fractal > > > dimensions. > > > > > > In the bug-report the first post shows a stunning lack of understanding >about > > > maths, roughly along the lines of demanding that the spreadsheet program >should > > > give £640 in my example of adding numbers. > > > > > > " > > I definitly see this as a bug and confirm it. Here's what I did: > > > > 1: Input "=-3^2+4" into a spreadsheet cell, result is 13 > > 2: Input "=4-3^2" into another cell, result is -5 > > 3: Input "=-(3^2)+4" into a third cell, result is -5 > > > > The problem here seems to be that the program attaches the negative sign > > to >the > > 3 in step one before doing the square, which it should not, unless >manipulated > > by parentheses like this: "(-3)^2". > > " > > > > In 1 the result is 13 because the first function done is -3 x -3 = 9, and >then > > > add the 4 to give 13 > > In 2 the result is due to an ambiguity that is normally resolved by using >the > > > standards method of afaik 3 x 3 = 9, and then 4 - 9 = -5 People with > > maths > > skills generally realise there is a potential problem with the ambiguity >here > > > and might try fixing it by using brackets eg = 4 + (-3^2) which gives us > > 13 > > 'obviously' since the inside of the bracket is done before applying the >stuff > > > outside the brackets. > > > > In 3 the result is -5 because the bracketed stuff is done first giving us > > +9 > > > again, then outside the bracket that is made -+9 = -9 and then the 4 is >added as > > > expected. > > > > > > This is maths, not spreadsheet stuff, unless i made a mistake in how #2 >should > > > be treated according to the Bodmas standards (in which case the bug-report >needs > > > to be fixed asap) but afaik i'm right. Even if i am wrong this is not >really a > > > job for documentation except as a brief note that 'common-sense' sometimes > > over-rides Bodmas but will hopefully be fixed soon. > > > > Regards from > > Tom :) > > > > > > > > > > > > ________________________________ > > From: Regina Henschel <rb.hensc...@t-online.de> > > To: documentation@global.libreoffice.org > > Sent: Fri, 10 June, 2011 23:39:01 > > Subject: Re: [libreoffice-documentation] Re: Collecting small things in > > the >Wiki > > > > Hi Tom, > > Tom Davies schrieb: > > > >> Hi :) > >> 3^2 does =9 ? > >> > > That's not the problem. But -3^2 result in 9 and that is the problem. > > http://openoffice.org/bugzilla/show_bug.cgi?id=26755 > > > > Kind regards > > Regina > > > > -- Unsubscribe instructions: E-mail to >documentation+h...@global.libreoffice.org > > Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette > > List archive: http://listarchives.libreoffice.org/global/documentation/ > > All messages sent to this list will be publicly archived and cannot be >deleted > > > > > > > Hi Tom. > I think it is bedmas - brackets, exponentiation, division, > multiplication, addition, subtraction. > There will be a mathematical standard for this, so I suppose we are > theorizing. > To remove all doubt, if you wanted (-3)^2 you would use the brackets > thus and if you wanted -(3^2) you would bracket that way. If there is no > "Standard" then may be with a leading '-' sign LO should ask or auto > correct to one of the bracketed options so it is clear what LO will do > with the number. I have always taken -3^3 = -27 same as LO does now, was > like that throughout university, but who is to say it is correct. > steve > Hi :) Yes the o in Bodmas doesn't make much sense and is not intuitive but i think it's meant to mean "Orders" referring to orders, powers, indices & exponents, NOT "omg not this again". In the US they don't have Brackets, they have simplified it to Parenthesis so a common mnemonic there is Pedmas. Oh and they simplified Exponents to Exponentiation along with dialogues to dialogz and Catherine to Katz. I cheekily use tho instead of though but it hasn't kort-on yet. http://en.wikipedia.org/wiki/Order_of_operations#Mnemonics Here are guides to show what level of maths we are talking about http://www.primaryresources.co.uk/maths/mathsC3.htm http://www.mathsisfun.com/operation-order-bodmas.html Primary is about equivalent of Elementary in the US. It's from about 4 to about 12 with some regional variations of 1 year, ie sometimes 3 to 11. The problem and ambiguity arise in computing because there is no difference between - 1 and -1 in computers but in handwritten notes it is easier to distinguish whether it is a value of (-1) or the value is (1) and then needs to be subtracted from whatever precedes the -1 (such as the implied 0). There is a note halfway down this page (or halfway up) about problems with computers and calculators. http://www.purplemath.com/modules/exponent5.htm At school i was told-off for writing a 9 that looked like a 7. I tried to explain that it was a 7 but that further annoyed the teacher who demanded that i explain why it looked like a 9. There is just no arguing with some people. I think that compatibility with Excel is important and i am not sure if we should follow their way or the Internationally agreed standards as taught in primary school (except to business people). Regards from Tom :) -- Unsubscribe instructions: E-mail to documentation+h...@global.libreoffice.org Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette List archive: http://listarchives.libreoffice.org/global/documentation/ All messages sent to this list will be publicly archived and cannot be deleted
