# a rant about math **URL:** \ **Category:** The BBQ Pit\ **Created:** [January 12, 2003, 3:55pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144 "2003-01-12T15:55:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![sotally\_tober](https://avatars.discourse-cdn.com/v4/letter/s/46a35a/32.png) [@sotally\_tober](https://boards.straightdope.com/u/sotally_tober)\ **Post date:** [January 12, 2003, 3:55pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/1 "2003-01-12T15:55:07Z")
stupid, stupid, stupid why do so many people think root 9 is plus minus three??? the root of nine is three. period. no buts about it. how about minus three then, you say. x^2=9 x= plus minus sqrt 9 x= plus minus 3. arghhhhhhhhhh why are people so dense! ignore me. this is just a rant. there. i feel much better. ---
**Author:** ![kitarak](https://avatars.discourse-cdn.com/v4/letter/k/898d66/32.png) [@kitarak](https://boards.straightdope.com/u/kitarak)\ **Post date:** [January 12, 2003, 4:36pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/2 "2003-01-12T16:36:00Z")
Ok. For ranting about such a petty subject you’ve left yourself wide open. 🙂 1. Capital letters are your friend. You’ve almost mastered punctuation (remember periods at the end of sentences, only one ? is neccesary, and questions end with a ?, not a !), now try capitalising the first word in any given sentence. It makes your posts far more legible. 2. It’s maths. No, I don’t care if you’re American. We came first, therefore we’re right. Comply or we shall assault you with posh accents. Anyway, the square root of numbers is ill-define unless you’re considering a particular branch cut of the complex plane (or a riemann surface I think, but I’m not entirely sure what those are). The square root of a number is thus whatever you wan’t it to be. +/- 3 is correct if you want to define the inverse of a non-injective function as the pre-image sets of points. It’s generally a pretty good way to do it IMO, but depends on context. That’s the problem with ranting about maths. There’s always some pompous mathematician lurking around the corner who knows more about it. 😉 ---
**Author:** ![Myrr21](https://avatars.discourse-cdn.com/v4/letter/m/e495f1/32.png) [@Myrr21](https://boards.straightdope.com/u/Myrr21)\ **Post date:** [January 12, 2003, 5:10pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/3 "2003-01-12T17:10:06Z")
Umm, what the hell are you talking about? ---
**Author:** ![Elza\_B](https://avatars.discourse-cdn.com/v4/letter/e/6a8cbe/32.png) [@Elza\_B](https://boards.straightdope.com/u/Elza_B)\ **Post date:** [January 12, 2003, 5:18pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/4 "2003-01-12T17:18:03Z")
I ain’t got much book-larnin’ when it comes to math. My checkbook is a mess. I’m probably one of the above people about whom you’re ranting. 😃 Ava ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [January 12, 2003, 5:39pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/5 "2003-01-12T17:39:07Z")
**sotally tober** - what’s the weather like on your planet? ---
**Author:** ![mhendo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mhendo/32/3159_2.png) [@mhendo](https://boards.straightdope.com/u/mhendo)\ **Post date:** [January 12, 2003, 5:41pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/6 "2003-01-12T17:41:58Z")
**kitarak** wrote: > [@](#): > > 1. It’s maths. No, I don’t care if you’re American. We came first, therefore we’re right. Comply or we shall assault you with posh accents. Damn right! This economizing on the letter “s” really struck me when i moved to the States. Try going into a clothing store - it’s even worse. There, you will find a sale on a nice wool PANT. It’s “pants,” you stupid fuckwits, unless perhaps you’re selling a garment with only one leg. ---
**Author:** ![racinchikki](https://avatars.discourse-cdn.com/v4/letter/r/eada6e/32.png) [@racinchikki](https://boards.straightdope.com/u/racinchikki)\ **Post date:** [January 12, 2003, 5:49pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/7 "2003-01-12T17:49:42Z")
I have never seen “pant” in the singular. It might be a regional usage. ---
**Author:** ![The\_Wrong\_Girl](https://avatars.discourse-cdn.com/v4/letter/t/b782af/32.png) [@The\_Wrong\_Girl](https://boards.straightdope.com/u/The_Wrong_Girl)\ **Post date:** [January 12, 2003, 6:02pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/8 "2003-01-12T18:02:08Z")
The only place I’ve seen “pant” in the singular is places like the Gap or the Limited, where they sell things like the “boot-leg pant” and the “chino pant.” So bitch if you want, but as far as I know, it’s only clothing stores that say that. ---
**Author:** ![magog](https://avatars.discourse-cdn.com/v4/letter/m/fbc32d/32.png) [@magog](https://boards.straightdope.com/u/magog)\ **Post date:** [January 12, 2003, 6:03pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/9 "2003-01-12T18:03:36Z")
No, **kitarak** has it right (except for that silly “maths” thing 🙂 ): -3[sup]2[/sup] and 3[sup]2[/sup] both equal 9. Of course, the only way you can get x[sup]2[/sup] = -9 is if you use your imagination. I haven’t seen “pant” either (as a garment, that is, not a way of a dog to get rid of excess heat), except for the term “pant suit”. ---
**Author:** ![mhendo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mhendo/32/3159_2.png) [@mhendo](https://boards.straightdope.com/u/mhendo)\ **Post date:** [January 12, 2003, 6:24pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/10 "2003-01-12T18:24:47Z")
> [@](#): > > \*Originally posted by The Wrong Girl \* > \*\*The only place I’ve seen “pant” in the singular is places like the Gap or the Limited, where they sell things like the “boot-leg pant” and the “chino pant.” So bitch if you want, but as far as I know, it’s only clothing stores that say that. \*\* True, but that doesn’t make it any more correct. And i’ve never seen this usage outside the US, although that doesn’t mean much - it could be common in the clothing industry internationally for all i know. For example: From [this site](http://www.barefootyoga.com/hemp/mens_pants.html): > [@](#): > > This unique pant offers the look and feel of linen with superior function and durability. From [this site](http://www.1800malls.com/oakley-clothing.html): > [@](#): > > Using high tech fabrics and Oakley style, the Unobtainium Pant defines winter clothing for the 21st Century. ---
**Author:** ![ultrafilter](https://avatars.discourse-cdn.com/v4/letter/u/3d9bf3/32.png) [@ultrafilter](https://boards.straightdope.com/u/ultrafilter)\ **Post date:** [January 12, 2003, 6:43pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/11 "2003-01-12T18:43:14Z")
Sadly, the exponential function is not, in general, single-valued. It gets worse once you use complex arguments; then it has infinitely many values in some cases. Complex analysis is fascinating, but it sucks. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [January 12, 2003, 6:51pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/12 "2003-01-12T18:51:12Z")
sotally tober, you are, of course wrong. The definition of “square root of 9” is any number which when multiplied by itself equals nine and, so, (-3) fits the bill perfectly. ---
**Author:** ![kitarak](https://avatars.discourse-cdn.com/v4/letter/k/898d66/32.png) [@kitarak](https://boards.straightdope.com/u/kitarak)\ **Post date:** [January 12, 2003, 6:56pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/13 "2003-01-12T18:56:48Z")
Actually, despite me being picky, in common usage he’s right. The square root of a positive real number is defined to be positive. My point was merely that there a lot of other senses you can mean ‘the square root’ in which he isn’t correct. Ultrafilter: Wash that mouth out with soap. Complex analysis doesn’t suck at all, it’s marvelous! So there. 😛 ---
**Author:** ![The\_Wrong\_Girl](https://avatars.discourse-cdn.com/v4/letter/t/b782af/32.png) [@The\_Wrong\_Girl](https://boards.straightdope.com/u/The_Wrong_Girl)\ **Post date:** [January 12, 2003, 7:00pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/14 "2003-01-12T19:00:00Z")
> [@](#): > > \*Originally posted by mhendo \* > **True, but that doesn’t make it any more correct. And i’ve never seen this usage outside the US, although that doesn’t mean much - it could be common in the clothing industry internationally for all i know.** Google brought these up in a matter of seconds: [http://www.sportsconnection.co.uk/products/34157340/](http://www.sportsconnection.co.uk/products/34157340/) (The “Sanded Twill Pant”) and [http://www.wheelbase.co.uk/trolleyed/13/21/187/](http://www.wheelbase.co.uk/trolleyed/13/21/187/) (The “Burton Tactic Vent Pant”) So, it’s not just the U.S. where “pant” is used. ---
**Author:** ![Tansu](https://avatars.discourse-cdn.com/v4/letter/t/67e7ee/32.png) [@Tansu](https://boards.straightdope.com/u/Tansu)\ **Post date:** [January 12, 2003, 7:08pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/15 "2003-01-12T19:08:53Z")
Burton Tactic Vent Pant would be a great SDMB uner name. ---
**Author:** ![80sHairMetalMaven](https://avatars.discourse-cdn.com/v4/letter/8/ed655f/32.png) [@80sHairMetalMaven](https://boards.straightdope.com/u/80sHairMetalMaven)\ **Post date:** [January 12, 2003, 7:34pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/16 "2003-01-12T19:34:23Z")
I confess to being one of those clueless, maths-inhibited people you’re probably ranting about. But I also have an excuse. I’m learning disabled!WHOOHOO!GO RETARDS!😃 IDBB ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [January 12, 2003, 9:56pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/17 "2003-01-12T21:56:11Z")
\>\> The square root of a positive real number is defined to be positive. Where? I have never heard such thing. The definition I know of “square root of 9” is any number which when multiplied by itself equals nine and, so, (-3) fits the bill perfectly. And it could be a complex number as well. If you can find a turnip which when multiplied by itself yields 9 then that turnip is a square root of 9. ---
**Author:** ![Enderw24](https://avatars.discourse-cdn.com/v4/letter/e/ba9def/32.png) [@Enderw24](https://boards.straightdope.com/u/Enderw24)\ **Post date:** [January 12, 2003, 10:03pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/18 "2003-01-12T22:03:40Z")
So, in essence, the OP is saying “I hate people who try to correct me when I’m obviously wrong.” What…we have here is…failure…to communicate. ---
**Author:** ![Cabbage](https://avatars.discourse-cdn.com/v4/letter/c/f07891/32.png) [@Cabbage](https://boards.straightdope.com/u/Cabbage)\ **Post date:** [January 12, 2003, 10:08pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/19 "2003-01-12T22:08:25Z")
By convention, in order to make the square root a _function_, the square root of a nonnegative number is commonly defined to be a _nonnegative_ number; so the square root of 9, for example, is indeed 3, and not -3. [http://mathforum.org/library/drmath/view/52989.html](http://mathforum.org/library/drmath/view/52989.html) ---
**Author:** ![gobear](https://avatars.discourse-cdn.com/v4/letter/g/8dc957/32.png) [@gobear](https://boards.straightdope.com/u/gobear)\ **Post date:** [January 12, 2003, 10:25pm UTC](https://boards.straightdope.com/t/a-rant-about-math/148144/20 "2003-01-12T22:25:42Z")
When come back, bring _pi_ [Next page](https://boards.straightdope.com/t/a-rant-about-math/148144.md?page=2)