Difference between revisions of "Matrix"

Latest revision as of 12:23, September 17, 2017

For the 1999 film, see The Matrix.

A matrix (pl.: "matrices," Latin origin) is a complex ordering, in deliberate fashion, of numerals. In mathematics, a "matrix" is a regular grid of numbers, which may be manipulated and solved through intermediate-level algebra. Matrix algebra is usually taught in sophomore high school level mathematics.

More formally, a matrix is an example of a rank-2 tensor.

Alternately, a matrix may also be a complex ordering of a group of equivalent objects, especially where the order is imposed to gain incidental benefit from the synergy of the networked objects.

Mathematics

In mathematics, matrices can be manipulated in a variety of ways, including addition and multiplication.

Addition of matrices

To add two matrices, one would add their respective elements. For example:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \begin{bmatrix} x & y & z \\ 1 & 3 & 5 \\ 0 & 2 & 0 \end{bmatrix} + \begin{bmatrix} 0 & 3 & 1 \\ 4 & 3 & {x+2} \\ 0 & 4 & v \end{bmatrix} }

would equal

${\begin{bmatrix}{x+0}&{y+3}&{z+1}\\{1+4}&{3+3}&{5+(x+2)}\\{0+0}&{2+4}&{0+v}\end{bmatrix}}={\begin{bmatrix}x&{y+3}&{z+1}\\5&6&{x+7}\\0&6&v\end{bmatrix}}$

Multiplication of matrices

To multiply two matrices, use the rule for finding the product of two matrices:

$(AB)_{ij}=\sum _{k}A_{ik}B_{kj}$

However, not every pair of matrices can be multiplied. In order for matrices $A$ and $B$ to be compatible for multiplication, the number of columns in $A$ must equal the number of rows in $B$ . If Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} is an Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle m \times n} matrix and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B} is an Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n \times p} matrix, the product matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AB} will have Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle m} rows and Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle p} columns.

Matrix multiplication is associative. However, matrix multiplication is not commutative. That is, it is possible for Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AB \neq BA} .

The Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n \times n} identity matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle I_n} satisfies the property:

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AI_n = I_n A = A}

for all Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n \times n} matrices Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} .

Moreover, every square matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A} with nonzero determinant has an inverse matrix Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle B} such that

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle AB = BA = I_n}

This means that for every positive integer Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n} , the set of all Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle n \times n} matrices with nonzero determinant form a group under matrix multiplication. This group is known as the general linear group Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle GL_{n}(\mathbb{R})} .

Matrix concepts

Basic concepts

Advanced concepts

@@ Line 1: / Line 1: @@
 ''For the 1999 film, see [[The Matrix]].''
-A '''matrix''' (pl.: "matrices," [[Latin]] origin) is a complex ordering, in deliberate fashion, of [[numeral|numerals]].  In [[mathematics]], a "matrix" is a regular grid of numbers, which may be manipulated and solved through intermediate-level [[algebra]].  Matrix algebra is usually taught in [[sophomore]] [[high school]] level mathematics.
+A '''matrix''' (pl.: "matrices," [[Latin]] origin) is a complex ordering, in deliberate fashion, of [[numeral]]s.  In [[mathematics]], a "matrix" is a regular grid of numbers, which may be manipulated and solved through intermediate-level [[algebra]].  [[Matrix algebra]] is usually taught in [[sophomore]] [[high school]] level mathematics.
 More formally, a matrix is an example of a rank-2 [[tensor]].
@@ Line 11: / Line 11: @@
 ===Addition of matrices===
-For example, to add two matrices, one would add their respective elements, thus:
+To add two matrices, one would add their respective elements.  For example:
 <math>\begin{bmatrix}
@@ Line 36: / Line 36: @@
 ===Multiplication of matrices===
-To multiply two matrices, one uses the rule "go along the rows and down the columns". This is best illustrated by a specific example: a matrix times a vector:
+To multiply two matrices, use the rule for finding the product of two matrices:
-<math>\begin{bmatrix}
+<math>
-a & b \\
+(AB)_{ij}=\sum_k A_{ik}B_{kj}
-c & d
-\end{bmatrix} \begin{bmatrix}
-e \\ f
-\end{bmatrix}=\begin{bmatrix}
-ae+bf \\
-ce+df \end{bmatrix}
 </math>
-It is important to note that matrix multiplication is not commutative: in general, <math>AB \neq BA</math> for two matrices <math>A</math> and <math>B</math>. This has important consequences in [[quantum mechanics]].
+However, not every pair of matrices can be multiplied.  In order for matrices <math>A</math> and <math>B</math> to be compatible for multiplication, the number of ''columns'' in <math>A</math> must equal the number of ''rows'' in <math>B</math>.  If <math>A</math> is an <math>m \times n</math> matrix and <math>B</math> is an <math>n \times p</math> matrix, the product matrix <math>AB</math> will have <math>m</math> rows and <math>p</math> columns.
-To see why matrix multiplication works the way it does, we will use [[suffix notation]]. Consider first forming the product of two matrices, <math>AB</math>, which is itself a matrix. Then form the product <math>ABx</math>. Matrix multiplication is associative, so we can consider this as either <math>(AB)x</math> or <math>A(Bx)</math>. In suffix notation,
+Matrix multiplication is [[associativity|associative]].  However, matrix multiplication is ''not'' [[commutativity|commutative]].  That is, it is possible for <math>AB \neq BA</math>.
-<math>
+The <math>n \times n</math> [[identity matrix]] <math>I_n</math> satisfies the property:
-\sum_j(AB)_{ij}x_j = \sum_k A_{ik}(Bx)_k=\sum_{j,k}A_{ik}B_{kj}x_j
+<center><math>AI_n = I_n A = A</math></center>
-</math>
+for all <math>n \times n</math> matrices <math>A</math>.
-The vector <math>x</math> is arbitrary, so we can therefore deduce the rule for finding the product of two matrices:
+Moreover, every square matrix <math>A</math> with nonzero [[determinant]] has an inverse matrix <math>B</math> such that
+<center><math>AB = BA = I_n</math></center>
-<math>
+This means that for every positive integer <math>n</math>, the set of all <math>n \times n</math> matrices with nonzero determinant form a [[group]] under matrix multiplication.  This group is known as the [[general linear group]] <math>GL_{n}(\mathbb{R})</math>.
-(AB)_{ij}=\sum_k A_{ik}B_{kj}
-</math>
 ===Matrix concepts===
@@ Line 80: / Line 74: @@
 *[[Basis]]
-*[[Diagonalizeable]]
+*[[Diagonalizable]]
 *[[Eigenspace]]
 *[[Eigenvalue]]
@@ Line 96: / Line 90: @@
 *[[Resultant]]
 *[[Span]]
-*[[Systems of linear equations]]
+*[[Linear equations]]
 *[[Transcriptor]]
 *[[Wronskian]]
-[[Category:Linear algebra]]
+[[Category:Linear Algebra]]
 [[Category:Computers]]