View Full Version : What is the square root of minus 1?
What is the square root of -1?
My pal's hubby asked me to post this.
Get yer neurons and synapses going!
What is the square root of -1?
My pal's hubby asked me to post this.
Get yer neurons and synapses going!
Why does your pal's hubby have any interest in the neurons and synapses of the orger brain?
He's doing research on public attitudes to learning and he thinks we are good guinea pigs. He's had too many shirazes and I'm going to send them home this minute because they both have work tomorrow. I have the morning off. :)
What is the square root of -1?
My pal's hubby asked me to post this.
Get yer neurons and synapses going!
Nope - not really. Came on here to chill out.
Just wondering why you've not directed your "pal's hubby" in the direction of Mr Google ......?
Sorry - Edited to say - just noticed Ojibwa's post - but now I'm wondering ..... why your pal's hubby needs to know the answer anyway .....?
He's doing research on public attitudes to learning and he thinks we are good guinea pigs. He's had too many shirazes and I'm going to send them home this minute because they both have work tomorrow. I have the morning off.
I don't really understand how this shows anything about attitudes to learning. It seems more a matter of you know the answer, or don't, or perhaps are able to work it out. But I don't mind being a guinea pig, and any good diversion is welcome at the minute :).
Enjoy your morning off, Crayola. I wish I had one tomorrow.
Lolabelle
14-Sep-06, 05:53
Math was never my strong point and I have absolutely no idea how to even work it out. I tried on the calculator and came up with "0" and as this is not an option on the poll, I guess I did not get it.
Never mind, hopefully you will be so kind as to tell us all how to do this calculation???? Please. I may not be much chop at this kinda thing, but once my curiousity is aroused, I want to know how and what is the answer.
j4bberw0ck
14-Sep-06, 07:00
It's an old, old chestnut. I won't ruin the poll, but my maths teacher (and my father as well :roll: ), 35 years ago, used to treat this question like a sort of shiny talisman, to be kept carefully and brought out now and again for polishing. Never anything useful, of course, like what it means or what it's useful for or why it's important; I doubt either of them knew. And I have to confess I don't know either. :lol:
porshiepoo
14-Sep-06, 08:40
Well I do remember something of my maths days and by my reckoning it's i.
I messed up the poll. One choice was meant to be 'it doesn't exist'. Sorry.
The attitudes to learning bit comes from responses to the question, not from the poll answers. It's to do with how people approach questions they don't know much about, He knows the answer already.
I messed up the poll. One choice was meant to be 'it doesn't exist'. Sorry.
The attitudes to learning bit comes from responses to the question, not from the poll answers. It's to do with how people approach questions they don't know much about, He knows the answer already.
Wow one of Crayola's spells gone wrong!!!!! Stay off the Vino Crayola[lol]
Witchcraft is a black art. Even for blonde witches. :lol:
I answered it but got it wrong duhhhh....... it does not exist! A square root is a number that multiplied by itself gives the original numer, I think....if memory does not fail me ( and it has tended to fail me more often now than it used to). (Example: 2x2 = 4 square root of 4 is 2; 3x3=9 square root of nine equals 3)
The only way to get a negative number in multiplication is to multiply a positive with a negative (positive x positive = positive; negative x negative = positive). So...... the two numbers you would have to multiply would be (+1) x (-1)= -1 ... they are not the same number therefore not a square root. there cannot be square roots of negative numbers then.
PS: I liked this one.
j4bberw0ck
14-Sep-06, 13:25
there cannot be square roots of negative numbers then.
Oh no! (http://www.google.co.uk/search?client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial_s&hl=en&q=square+root+of+-400&meta=&btnG=Google+Search) :lol:
LOL! I am lost for words...this is just what I was thinking...... hmmmmm..... math was a long time ago...I need to rest the few brain cells I have left.
Hm....I just cheated and used a calculator and mine says invalid input for this fuction........whatever negative number I use........ this is KILLING ME! CRAYOLA.... the answer, pretty please with icecream and strawberries
I answered it but got it wrong duhhhh....... it does not exist! A square root is a number that multiplied by itself gives the original numer, I think....if memory does not fail me ( and it has tended to fail me more often now than it used to). (Example: 2x2 = 4 square root of 4 is 2; 3x3=9 square root of nine equals 3)
The only way to get a negative number in multiplication is to multiply a positive with a negative (positive x positive = positive; negative x negative = positive). So...... the two numbers you would have to multiply would be (+1) x (-1)= -1 ... they are not the same number therefore not a square root. there cannot be square roots of negative numbers then.
PS: I liked this one.
Thought I liked maths problems but - pleeeeese. My brain is tired just thinking about this. Will have to go and lie down.
The bruce informs me that it is both i and -i and muttered about imaginary numbers and
fundamental algebraic formulae which might or might not be a bit like fundamental islamic terrorists and souls but then it might not be thats how much sense it makes for me.
I dont pretend to understand but i did make his vote for him
LOL... you can't have square roots of negative numbers unless they are complex IMAGINARY numbers...... now I know mathematicians are nuts! If only this would work for other things in life....like inventing imaginary cash or winning the imaginary lotto!
j4bberw0ck
14-Sep-06, 13:51
That's it in a nutshell, as far as I understand it. For calculation purposes the value of (square root -1) is assigned a value i by mathematicians since it isn't a "real" number. Therefore (square root -400) = 20i ; 20 times the value of i, whatever it may be.
But my maths is pretty rudimentary so I'm going to stop there! :lol:
porshiepoo
14-Sep-06, 15:24
See! I guess none of you believed me when I gave you the answer way back! :lol:
Hmmmmmm but having sat down with paper and thought about my ancient math memories I seem to now think that as all square roots of 'real' numbers have 2 numbers then the actual correct answer for this would be i or -i?????????
Why do scientists have to complicate things by introducing imaginary numbers? Can't they just stick to the real ones we all are aware of?
Come on Crayola whats the answer? Even I'm having doubts about my mathematical abilities now! LOL.
didnt think it could be done so got out the calculator cheating i ken but its a cheap one and it didnt work so i'm no further on.
Colin Manson
14-Sep-06, 17:29
The answer is i
http://en.wikipedia.org/wiki/Imaginary_unit
i but it was j when i was young
Colin Manson
14-Sep-06, 19:25
Alternative notation
In electrical engineering and related fields, the imaginary unit is often written as j to avoid confusion with electrical current as a function of time, traditionally denoted by i(t) or just i. The Python programming language also uses j to denote the imaginary unit.
I think that using a complicated form of differentiation you could calculate a theoretical answer........
but in practical terms you can't have a square root for a negative number.
porshiepoo
14-Sep-06, 19:44
I think that using a complicated form of differentiation you could calculate a theoretical answer........
but in practical terms you can't have a square root for a negative number.
Think you can now! Wasn't the i invented (or whatever) so that you could find and use the square root of an negative number? It was then termed an 'imaginary' number hence the 'i'? Or have I gone all thick again??? :confused
Where is our white knight when we need him to come charging in and explain all of this to us. DrSzin stop trying on kilts and get over here before our brains explode.
futurelegends
14-Sep-06, 21:24
I'm sure when I was at College it was -j , so I'll say -i.
Where is our white knight when we need him to come charging in and explain all of this to us. DrSzin stop trying on kilts and get over here before our brains explode.
The good doc is certainly conspicuous by his absence! Perhaps he's away at some exotic location for the Szin in Kilts photo shoot! ;)
I didn't think my input was needed.
Porshiepoo gave the answer, explained why there are two roots, and explained why imaginary numbers are needed. Meanwhile, Colin's link to the Wikipedia page provided enough detail to sink a battleship in dihydrogen monoxide. :cool:
As Wikipedia explains in detail, there are two solutions to the equation
http://upload.wikimedia.org/math/3/4/4/344efc164336458b919007f8c13eb694.png,
and these values for x, namely x = i and x = -i, are called the roots of the equation. The imaginary number i is defined by its square, namely i x i = -1. By convention, i (as opposed to -i) is usually called the square root of -1. Similarly, we usually say that 2 (as opposed to -2) is the square root of 4.
If I were marking an exam I would give full marks to the last and third-last answers, but take one mark off for the second-last one - for being obtuse! The answer "it doesn't exist" is ok if you restrict your answer to the set of real numbers.
There's a reasonable introduction to complex numbers on this Wikipedia page (http://en.wikipedia.org/wiki/Complex_number), but it gets hard quite quickly.
Alternative notation
In electrical engineering and related fields, the imaginary unit is often written as j to avoid confusion with electrical current as a function of time, traditionally denoted by i(t) or just i.Yup, and vice versa for physicists. We usually use i for the square root of -1, and j for the current density (the charge passing through unit area per unit time.)
mostlyharmless
15-Sep-06, 00:23
Imaginary Numbers grievous....
I doubt I will ever encounter a situation where I will have to deal with square roots of negative numbers. How can it be done ? After all, a positive number squared or a negative number squared will always equal a positive number?!
Mathematicians[how clever] have designated a special number 'i' which is equal to the square root of minus 1. Then, it follows that i2 = -1. To determine the square root of a negative number (-16 for example), take the square root of the absolute value of the number (square root of 16 = 4) and then multiply it by 'i'. So, the square root of -16 is 4i.
As a double check, we can square 4i (4*4 = 16 and i*i =-1), producing -16.
All negative square roots are called "imaginary numbers" (now you know where that letter 'i' comes from)........great!
well THAT cured my insomnia!!
So we've got the answer then: i.....an imaginary number.
I suppose -1 is imaginary anyway because how can you have -1 apples? If you've got -1 apples you might as well have -7654 apples......it'll not make a lot of difference. ;)
What I want to know is......how many "i"s does it take to change a lightbulb?
What I want to know is......how many "i"s does it take to change a lightbulb?
I would guess only one, if it was a negative, square lightbulb....
;)
j4bberw0ck
15-Sep-06, 12:14
I would guess only one, if it was a negative, square lightbulb....;)
........and especially if the i was rooted to the spot........
Thank you all for taking part and for taking it seriously.
I checked back as far as post 25, at which point I took two asprin for my headache and went to lie in a darkened room.
What is the square root of -1?
My pal's hubby asked me to post this.
Get yer neurons and synapses going!
Minus one is pi =3.141592 etc multiplied by i so the square root of minus one does not exist!!!!!
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