Wikipedia:Reference desk/Archives/Mathematics/2006 November 6

= November 6 =

On the IT desk
I posted a question on the Computing/IT desk about programming a game into my calculator. When I scrolled up to a question asked a day or two ago about another TI calculator, I saw that it was never answered. Just want to make sure I'm getting anybody who knows about it TI-Basic to respond and I figured this was another place I could ask for someone to take a look. I don't think that this qualifies as a double post either, so please don't get on my back about it. schyler 04:58, 6 November 2006 (UTC)

Daily Geometry
Do you use Geometry in you life daily?

Anwser either yes, no, or "I haven't ever noticed. —The preceding unsigned comment was added by 64.5.138.2 (talk • contribs) 13:56, November 6, 2006 (UTC).


 * Yes, every time I move from one place to another I consider distances and angles, using a mental map which is effectively a geometric diagram.--86.132.234.81 22:35, 6 November 2006 (UTC)


 * I have, absolutely (and I wasn't especially good at or interested in math in school.) I've used it in drawing and painting (especially in perspective) carpentry and crafts, and drafting as a designer. I have absolutely never used calculus though. Dina 23:32, 6 November 2006 (UTC)


 * Constantly. (And as I work in computer graphics, there has also been much combination between calculus and geometry.) - Rainwarrior 00:31, 7 November 2006 (UTC)


 * Yes, most certainly. Much of my work in marine ecology involves developing mathematical models.  These models would be incomprehensible without a firm understanding of geometry (along with a few other areas of math).  --TeaDrinker 03:24, 7 November 2006 (UTC)

Order of OPS
Hi I need help on my algebra homework. They give me a problem that looks like this. ..

- 8 + 3 - 2 + 7 = - 2

I need to figure out where the parenthesis go to make the statment true. How would I do this. I have about 9 of thes problems. please help me!!

--Devol4 14:44, 6 November 2006 (UTC)


 * With only four terms, there aren't too many different places to put parentheses. I think there are only 4 different things to try (unless you are allowed to introduce multiplication), so just try them out. - Rainwarrior 15:37, 6 November 2006 (UTC)


 * As Rainwarrior says, you will have to use "trial and error". You can cut down the work a bit by getting an idea of how big a change you need to make in the sum. For example


 * - 8 + 3 - 2 + 7 = 10 - 10 = 0


 * so if we want to make the sum -2 we need to reduce the sum by 2. We could achieve this by changing a +1 into a -1, but we don't have a +1 term in the expression. But 3-2=1, so if we can change the sign of both the +3 and the -2 terms, we are done. So we try


 * - (8 + 3 - 2) + 7 = -9 + 7 = -2


 * which works. Gandalf61 15:49, 6 November 2006 (UTC)


 * The appropriateness of Gandalf61's direct answer to a homework problem is disputed, and is being discussed on the talk page. Interested questioners and answerers should provide comments there.


 * The important thing to note here is that putting parentheses after + signs makes no difference: $$a+b-c=a+(b-c)=0+(a+b)-c$$. So you'll only ever need to introduce a left parenthesis after a minus sign.  Perhaps that will help with the other 8.  (As a side note, what does this have to do with algebra?  Sounds more like subpar recreational mathematics to me.)  --Tardis 17:13, 6 November 2006 (UTC)


 * Using the observation that left parentheses not directly following a minus sign are redundant, I see seven ways of putting parentheses, two of which produce −2. The other five all give different results: 0, −6, −14, −16, −20. --Lambiam Talk  22:11, 6 November 2006 (UTC)

The order of operations is "Please excuse my dear aunt sally" aka Parenthesses, exponents, multiplication, division, addition, subtraction! and like everyone said before do trial and error and figure it out on your own. Don't use wikipedia for solving homework problems. another good website is http://webmath.com/ please use it!