Editing 2028: Complex Numbers

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==Explanation==
 
==Explanation==
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{{incomplete|Created by a MATHEMATICIAN - Do NOT delete this tag too soon.}}
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The {{w|complex number}}s can be thought of as pairs <math>(a,\ b)\in\mathbb{R}\times\mathbb{R}</math> of real numbers with rules for addition and multiplication.
 
The {{w|complex number}}s can be thought of as pairs <math>(a,\ b)\in\mathbb{R}\times\mathbb{R}</math> of real numbers with rules for addition and multiplication.
  
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: <math>(a,\ b) \cdot (c,\ d)  = (ac - bd,\ ad + bc)</math>
 
: <math>(a,\ b) \cdot (c,\ d)  = (ac - bd,\ ad + bc)</math>
  
As such, they can be modeled as two-dimensional {{w|Euclidean vector|vectors}}, with standard vector addition and an interesting rule for multiplication. The justification for this rule is to consider a complex number as an expression of the form <math>a+bi</math>, where <math>i^2 = -1</math>, i.e. ''i'' is the square root of negative 1. Applying the common rules of algebra and the definition of ''i'' yields rules for addition and multiplication above.
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As such they are two-dimensional {{w|Euclidean vector|vectors}}, with an interesting rule for multiplication. The justification for this rule is to consider a complex number as an expression of the form <math>a+bi</math>, where <math>i^2 = -1</math>, i.e. ''i'' is the square root of negative 1. Applying the common rules of algebra and the definition of ''i'' yields rules for addition and multiplication above.
 
 
Regular two-dimensional vectors are pairs of values, with the same rule for addition, and no rule for multiplication.  
 
  
The usual way to introduce complex numbers is by starting with ''i'' and deducing the rules for addition and multiplication, but Cueball is correct to say that some uses of complex numbers could be modeled with vectors alone, without consideration of the square root of a negative number.
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Regular two-dimensional vectors are pairs of values, with the same rule for addition, and no rule for multiplication.
  
The teacher, [[Miss Lenhart]], counters that to ignore the natural construction of the complex numbers would hide the relevance of the {{w|fundamental theorem of algebra}} (Every polynomial of degree ''n'' has exactly ''n'' roots, when counted according to multiplicity) and much of {{w|complex analysis}} (calculus with complex numbers; the study of analytic and meromorphic functions), but she also agrees that mathematicians are too cool for "regular vectors." Just because the complex numbers can be interpreted through vector space, however, that doesn't mean that they ''are'' just vectors, any more than being able to construct the natural numbers from set logic mean that natural numbers are ''really'' just sets.
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The usual way to introduce complex numbers is by starting with ''i'' and deducing the rules for addition and multiplication, but Cueball is correct to say that complex numbers are really just vectors, and can be defined without consideration of the square root of a negative number.
  
In mathematics, a {{w|group (mathematics)|group}} is the pairing of a binary operation (say, multiplication) with the set of numbers that operation can be used on (say, the real numbers), such that you can describe the properties of the operation by its corresponding group. An {{w|Abelian group}} is one where the operation is commutative, that is, where the terms of the operation can be exchanged: <math> a \cdot b = b \cdot a</math> The title text argues that the "link" between algebra and geometry in "algebreic [sic] geometry" and "geometric algebra" is the operation in an Abelian group, such that both of those fields are equivalent.  Algebraic geometry and geometric algebra are mostly unrelated areas of study in mathematics. {{w|Algebraic geometry}} studies the properties of sets of zeros of polynomials. It runs relatively deep. Its tools were used for example in Andrew Wiles' celebrated proof of Fermat's Last Theorem. For its part, a {{w|geometric algebra| geometric algebra}} (a {{w|Clifford algebra| Clifford algebra}} with some specific properties) is a construct allowing one to do algebraic manipulation of geometric objects (e.g., vectors, planes, spheres, etc.) in an arbitrary space that has a resultant geometric interpretation (e.g., rotation, displacement, etc.). The algebra of quaternions, which is often used to handle rotations in 3D computer graphics, is an example of geometric algebra, as is the algebra of complex numbers. {{w|Metabelian group|Meta-Abelian groups}} (often contracted to metabelian groups) is a class of groups that are not quite abelian, but close to being so.  
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The teacher, [[Miss Lenhart]], counters that to ignore the natural construction of the negative numbers would hide the relevance of the {{w|fundamental theorem of algebra}} (Every polynomial of degree ''n'' has exactly ''n'' roots, when counted according to multiplicity) and much of {{w|complex analysis}} (the application of calculus to complex-valued functions), but she also agrees that mathematicians are too cool for "regular vectors."
  
Randall's joke in the title text is a wordplay combining the concepts of (meta-)abelian groups and change in the order of word orders with the general idea of "meta".
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In mathematics, a {{w|group (mathematics)|group}} is the pairing of a binary operation (say, multiplication) with the set of numbers that operation can be used on (say, the real numbers), such that you can describe the properties of the operation by its corresponding group. An {{w|Abelian group}} is one where the operation is commutative, that is, where the terms of the operation can be exchanged: <math> a \cdot b = b \cdot a</math> The title text argues that the "link" between algebra and geometry in "algebreic [sic] geometry" and "geometric algebra" is the operation in an Abelian group, such that both of those fields are equivalent.  Algebraic geometry and geometric algebra are mostly unrelated areas of study in mathematics. {{w|Algebraic geometry}} studies the properties of sets of zeros of polynomials. It runs relatively deep. Its tools were used for example in Andrew Wiles' celebrated proof of Fermat's Last Theorem. For its part, geometric algebra aka {{w|Clifford algebra| Clifford algebra}} is a construct allowing one to do arithmetic operations on vectors of a higher dimensional space. The algebra of quaternions, often used to handle rotations in 3D computer graphics, is an example of a Clifford algebra. {{w|Metabelian group|Meta-Abelian groups}} (often contracted to metabelian groups)
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is a class of groups that are not quite abelian, but close to being so.  
  
This comic is similar to the earlier Miss Lenhart comic [[1724: Proofs]].
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Randall's joke in the mouseover text is a wordplay combining the concepts of (meta-)abelian groups and change in the order of word orders with the general idea of "meta".
  
 
==Transcript==
 
==Transcript==
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{{incomplete transcript|Do NOT delete this tag too soon.}}
 
:[Cueball (the student) is raising his hand and writing with his other hand. He is sitting down at a desk, which has a piece of paper on it.]
 
:[Cueball (the student) is raising his hand and writing with his other hand. He is sitting down at a desk, which has a piece of paper on it.]
 
:Cueball: Does any of this really have to do with the square root of -1? Or do mathematicians just think they're too cool for regular vectors?
 
:Cueball: Does any of this really have to do with the square root of -1? Or do mathematicians just think they're too cool for regular vectors?
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[[Category:Comics featuring Miss Lenhart]]
 
[[Category:Comics featuring Miss Lenhart]]
 
[[Category:Math]]
 
[[Category:Math]]
[[Category:Analysis]]
 

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