imaginary numbers :
eleventeen
tenteen
threeteen
fiveteen
oneteen
twoteen
2006-07-18 05:44:53
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answer #1
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answered by Not_Here 6
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Imaginary numbers are, broadly speaking, numbers that are not real--they do not have a location on a real number line. However, they can be defined by a PROPERTY that they have.
I assume that by "iota" you mean i, which is commonly used to represent a number that, if you square it, you get -1. That is the DEFINITION of i: i^2 = -1. (I believe we use "i" because it stands for "imaginary", but don't quote me.)
Because of this property, powers of i follow an orderly pattern:
i^1 = i
i^2 = -1
i^3 = (i^2)(i) = (-1)(i) = -i
i^4 = (i^2)(i^2) = (-1)(-1) = 1
i^5 = (i^4)(i) = (1)(i) = i
i^6 = (i^5)(i) = (i)(i) = -1
... and so forth. Since i^4 = 1, we could say that i is a FOURTH ROOT of 1.
As for omega... I belive omega (which kind of looks like a "w") is used to represent a CUBE root of 1. In other words, w^3 = 1.
Obviously 1 itself is a cube root of 1, but there are two others as well, w and w^2. But w can be re-written using i as follows:
w = -1/2 + (sqrt(3)/2) i
Using that definition, you can verify for yourself that if you cube w, you get 1.
So i is a fourth root of 1, and w is a cube (third) root of 1.
(As for why omega us used, rather than some other symbol, your guess is as good as mine.)
2006-07-18 05:58:26
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answer #2
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answered by Matt E 2
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By the very definition of IMAGINARY numbers...They are IMAGINARY!!!!....why do we need imaginary numbers??? well because they can have real consequences!!!....for example iota squared is a real number ie -1.......thats why we need "imaginary numbers".......
iota and and omega are chosen completely for convience sake...iota[i]...stands for imaginary...omega of course means something that is not well known........
2006-07-18 05:51:16
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answer #3
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answered by OZ 1
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Mathematicians wanted to solve equations like x^2+1=0. Since there is no real number that can solve this, mathematicians said that one of the solutions is i. This leads of course to the other solution being -i. Although you may use iota (ι), I believe that it is more standard to use i as the square root of -1. This can also be known as a primitive 4th root of unity.
Omega (Ï) and zeta (ζ) are both used often for the same thing. That is a primitive n-th root of unity. This can be given as Ï=ζ=exp(2Ïi/n).
What is a primitive n-th root of unity in theory?
Well, let's first define an n-th root of unity.
An n-th root of unity is a number α (usually complex and not real, but can be real) such that α^n=1. Since 1^n=1, and (-1)^n=1 when n is even, 1 is always an n-th root of unity, and -1 is an n-th root of unity when n is even. Also Ï^n=(exp(2Ïi/n))^n = exp(2Ïi/n•n) = exp(2Ïi) = 1, so Ï is also an n-th root of unity (this is good, since we would want a primitive n-th root of unity to be an n-th root of unity).
So what is a primitive n-th root of unity? A primitive n-th root of unity Ï is an n-th root of unity and moreover all n-th roots of unity can be given by powers of Ï.
For n=3, we have Ï=exp(2Ïi/3) = cos(2Ï/3)+i•sin(2Ï/3) = -1/2+i•â3
and we have Ï^2=exp(2Ïi/3)^2 = exp(4Ïi/3) = cos(Ï/3)+i•sin(Ï/3) = -1/2-i•â3.
You will also notice that Ï^3=exp(2Ïi/3)^3 = exp(6Ïi/3) = exp(2Ïi) = 1, and (Ï^2)^3 = (^3)^2 = 1^2 = 1. Thus Ï, Ï^2, and Ï^3=1 are the 3rd roots of unity, and as stated they are all powers of Ï.
Also notice that for n=4, we have Ï=exp(2Ïi/4) = exp(Ïi/2) = cos(Ï/2)+i•sin(Ï/2) =i. Thus i is a primitive 4th root of unity. This can be checked by i^2=-1, so i^3=-1•i=-i and i^4=(-1)^2=1. These four numbers are all solutions of x^4=1, so that shows that all 4th roots of unity can be represented as powers of i. Thus i IS a primitive 4th root of unity.
2006-07-18 05:47:37
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answer #4
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answered by Eulercrosser 4
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sqrt(-1) is not a real number. So we call it imaginary. We use the symbol 'i' to denote it. we can now easily write the sqrt.s of -ve numbers in terms of i
Using this we can write sqrt(-4) as 2i or -2i
2006-07-18 05:51:59
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answer #5
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answered by newton of india 1
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Those are not imaginary numbers. You need to talk to your math and history professors and have them answer those questions.
2006-07-18 05:44:50
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answer #6
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answered by Nicole C 4
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