The square root of 9 is +/- 3. Just saying"3" is making it positive. Negative 3 times negative 3 equals nine, as does 3 times 3. Therefore, both need to be shown.
It’s not economizing – it just moved to the end of “sport” (hence “math” and “sports” rather than “maths” and “sport”). Much in the same way that American English takes the “at” out of “orientated” (“oriented”) and puts it in “obliged” (“obligated”). These things happen when languages get moved over long distances – some contents may settle during handling. 
And just how long have you been waiting for an opportunity to use that? 
well, well.
what a storm in a teacup my little rant has kicked up.
first, i’d like to state for the record i’m not a yank =P ; we use Queen’s english here where we come from.
i rigidly (or at least i’d like to think so) stick to Brit spelling and grammer for nearly every other thing.
‘math’ is my preference only because it’s so much ‘fuller’ and dignified than ‘maths’. most people leave out the ‘aitch’ sound when they pronounce ‘maths’ and it inadverdently becomes ‘mats’, which sounds ugly. when ‘math’ is used, people more than notice the ‘th’ at the back and make an extra effort to vocalise it.
well, this is my rant, and i’ll cry if i want to.
and i’ll stick to my point.
The square root of 9 is +3. ONLY.
It’s all very well saying, yeah… but the definition of a root is… blah… but just because -3 is a square root of 9 does NOT mean that sqrt 9 = -3.
Look carefully. There is a difference, though some may consider it minute. That was the whole point of my rant, however.
As I said **sailor **, a storm in the teacup.
Somebody must be able to think of something amusing to say in response to this, but my brain has fused… Your grammer’s just fine, ST… but we’re more concerned with grammar…
I don’t think I have heard the sqrt of 9 defined as only +3 since maybe 6th grade when the concept of sqrt was first being taught and I am graduating with my BSEE in June so my life for the last 5 years has been math.
If you say that the only sqrt of 9 is +3, and then in the next sentence say that another sqrt of 9 is -3, one of the statements must be false.
As magog wrote: -3[sup]2[/sup] and +3[sup]2[/sup] both equal 9.
Try taking a logic course. :wally
I’ve already posted one link showing that, sotally tober is correct. Here’s another:
http://mathworld.wolfram.com/SquareRoot.html
It’s all a matter of definition. If by “square root of b” you mean a number whose square is b, then b can have two square roots. But if you want to define “square root” as a function (and this is, in fact, commonly done), then the standard way is to define the square root such that it’s always nonnegative. In this sense, sotally tober is correct.
For the record, I also loved complex analysis. I think that it must be a Cambridge thing.
Although in my day the lecturer seriously sucked. I’m struggling to remember the name now, however. Began with a ‘K’. Bane of my life for 2 months and now I can’t even remember the name. Or the face.
There’s a lesson in there somewhere, if I can just figure it out.
pan
I don’t know? Why ARE people so dense? Such as those that believe that knowing math denotes whether or not a person is intelligent?
How insulting!! And thank you sooooooooo much for bringing up, yet once again, all the trauma of my youth.
Such as my parents (bless their souls, they meant well), giving me “pop quizzes” (QUICK now!! What’s 59 times 42??? {snapping fingers} hurry up, figure it out in your head!!! Come on!!), the third and eighth grade math teachers that passed the girls who wore skirts, good grades or not.
The first grade teacher (before I became math phobic, in fact probably WHY I became math phobic) who shamed me in front of the entire class for doing the worksheet of the little boy behind me because I finished first and was bored.
The college professor who told me, after I asked where I could get help and not fail his class, that people who didn’t just inherently understand math were psychologically sick.
Now, that being said, I understand the importance of math in the “workaday” world. I do not understand square roots, or much beyond simple addition and subtraction really.
I am NOT however, “stupid, stupid, stupid”. NOR are my fellow math phobics.
I would have ignored you had you qualified it with something like “why do people who profess to be good at math” or something like that.
But a sweeping generalization like the one you did post? Sorry.
You’re a brit and you distort the “proper” adage into “storm in a teacup”?
Shoes
Who is only 3/4 Brit.
Hmm. The current complex analysis lecturer (Dr Carne) is pretty good. Or so I remember from sneaking into the further analysis lecture last year. My head hurt, but that’s what you get if you try to tackle a course without having done any of the prerequisites. (I actually understood more than 2/3 of it in the end). I’ll be trying again this term from a more… enlightened… perspective. Certainly I thought he was a good lecturer when he taught Geometry. Further analysis is of course only the ‘little’ complex analysis course, so there may be worse to come.
Speaking of Cambridge, do you by any chance still live there or just an ex-student? If the former, get thee to MPSIMS (Here specifically.) Unless you’re put off by the idea of lots (actually, hardly any it seems) of scary little students.
Ahem. On topic now…
Nope, can’t be bothered. It’s a silly argument. x^1/2 = Exp ( 1/2 * Log(x)). Log(x) is multivalued, but so what? It works fine wherever I want it to work. (just not always at the same time).
CanvasShoes: You know, there are help groups for that. In time, you can be cured… 
::d&r::
No, seriously. It’s unfortunate that you don’t like maths but isn’t really a problem. Everyone has different strengths and while it’s nice to be good at everything (not speaking from experience here, believe me), it’s generally not possible. I’m sure you already know this, but basically I’m just trying to say that not all mathematicians believe that people who can’t quite grasp maths have something wrong with them.
And let me know if anyone says otherwise. I’ll force 'em to watch ‘Barney and the Teletubbies teach counting’ on a permanent loop for a week straight. Then we’ll see who’s put off maths. Muahaha.
LMAO Kit, and thank you for the encouragement. I was half joking and half serious. The college professor was the worst, he didn’t just tell me I was sick, he proceeded to rip apart my character for about 20 minutes. I was in tears by the time I left. I dropped the class and haven’t really delved into anything more complicated than my checkbook since then.
Though strangely, I am able to do the types of algebraic equations that are necessary for certain parts of my job. My bf is quite disgusted with me, lol. He says that I am one of the brightest people he knows, he doesn’t “get” why I can’t do math.
Someday I will get a really good tutor and try to unlock this mental block. Until then, I hope other mathematicians will view me, and those like me with a kind and tolerant eye.
Nitpick:
-3[sup]2[/sup] = -9
(-3)[sup]2[/sup] = 9
-lv
I would really like to have one of these, but I can never quite seem to get a hold of one…
3i^2 = -9
“But, it’s only imaginary”
Just to continue my own hijack (on the grounds that this thread is going nowhere fast anyway)…
Dr Carne now teaches Complex Analysis? Carne as is “Kerner”? Good lord. Yes, he’s fantastic - used to do the first year algebra course as well as a few other things in my day. Do you know that somewhere there is a web page devoted to his little sayings? Marvellous.
No, some other dickwad did it then. I remember he also did graph theory - a course that was also distinguished by having a reading list that soley consisted of books in German, except for one in Russian. Oh - and I had a Russian supervisor that couldn’t speak English. I dropped that course pdq, you will not be surprise to learn!
No, as a Cambridge mathmo I now make helluva money down in London. And I live in Surrey. But it’s only a couple of hours away and I have a friend that still lives there…
You must be joking. This is the most ridiculous trumped-up “try to make myself look clever but not succeed because the subject is so trivial” non-rant I’ve ever seen (almost).
Ah, that’s OK then.
Quite. Although I will point out that statistical financially speaking you very quickly lose interest in that negative root, let alone Riemannian surfaces!
[sub]Incidentally, Magdalene '95 - '98, before you ask[/sub]
pan
No, Carne and Kerner are two different lecturers. Kerner is lecturing Analysis I at the moment (or at least he was last year).
Hmm… Begins with a k. Russian/German… Err. Please tell me his name isn’t Kovalev? :eek: He’s going to be lecturing me on quadratic maths this term. If we get another bad quadratic lecturer I’m going to hunt down the idiot who’s assigning course lecturers and beat the crap out of him/her (metaphorically speaking of course).
We’ve had two bad linear maths and one bad quadratic lecturer so far (each course runs twice. You can pull linear maths forward, and then those who did can take quadratic in the first term of IB instead of the second one). After all, it’s not like they’re key courses or anything… ::cough:: Sorry. I’m bitter. Can you tell?
It’s good to know that those of us who sell out… err. I mean decide not to go into academia are well qualified for making oodles of cash. Gives me a backup plan.
(By the way, shame on you for not doing a part III :p)
Ah, thought I was misremembering Kerner. But I think I remember that he had an umlaut in there somewhere and thought that Cärne might be pronounced the right way. Clearly not - shame on me.
You’re OK. Was not Kovalev. In fact I don’t remember a Kovalev at all. No, this chap was very English. It’s really going to bug me now, so I’ll ask my friend who always remembers this stuff.
You’ve had a bed lecturer? The mathematics* department has… some bad lecturers? The horror!
Is Dr Death (or rather Dr De’Ath) still there? I remember that he used to shuffle in wearing a raincoat and just start writing on the OHP. Never said a word. Just wrote (illegibly) for an hour. No pre-printed notes either.
At least Dr Grimmit was entertaining though. Cravate and all. And the Algorithms and Bears guy - can’t remember any algorithms but I still know all about bears.
And you still want to do Part III do you? Never mind. That’ll be beaten out of you in short order. Bwahahahaha.
pan
*always “mathematics”. Never “maths” OR “math”. Shame on you for getting that one wrong.
Excellent Freudian slip there: “bed lecturers”. Wunderbar!