Showing posts with label Matrices. Show all posts
Showing posts with label Matrices. Show all posts

Sunday, May 8, 2016

XII - 11.24 Solution of a homogeneous system of linear equations - Video Lectures


Solving a Homogeneous System
NightingaleMath
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Thursday, May 5, 2016

XII - 11.14 Elementary transformations of Elementary Operations of a matrix - Video Lectures



XII -

11.14 Elementary transformations of Elementary Operations of a matrix - Video Lectures


1. Interchange of two rows or columns.
2. Multiplication of all elements of a row or column of a matrix by a non-zero scalar,
3. Addition to the elements of a row or column of the corresponding elements of any other row (to a row) or any other column (to a column) multiplied by a scalar k.


Elementary matrix: A matrix obtained from an identity matrix by a single elementary operation (transformation) is called an elementary matrix.

Elementary Operation of matrix - all three operations - Video


https://www.youtube.com/watch?v=1k7-qh3mj4k


Finding Inverse of a Matrix Using Elementary Transformations

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maths1122

XII - 11.13 Inverse of a matrix - Video Lectures



Let A be a square matrix of order n

If AB = In = BA

The B is inverse of A and is written as
A-1 = B



Theorems related to Inverses of matrices

1. Every invertible matrix possesses a unique inverse

2. A square matrix is invertible iff it is nonsingular.

3. A-1 = (1/|A|)adj A

4. Cancellation laws: Let A, B, and C be square matrices of the same order n. If A is a non-singular matrix, then

(i) AB = AC => B = C … (left cancellation law)
(ii) BA = CA => B = C … (right cancellation law)

This law is true only when |A| ≠ 0. Otherwise, there may be matrices such that AB = AC but B≠C.

5. Reversal law: If A and B are invertible matrices of the same order, then AB is invertible and

(AB) -1 = B-1A-1

6.If A,B,C are invertible matrices then
(ABC) -1 = C-1B-1A-1

7.If A is an invertible square matrix, then AT is also invertible and
(AT)-1 = (A-1)T

8. Let A be a non-singular square matrix of order n. Then

|adj A| = |A|n-1

9. If A and B are non-singular square matrices of the same order, then

adj AB = (adj B) (adj A)

10. If A is an invertible square matrix, then

adj AT = (adj A) T


11. If A is a non-singular square matrix, then

adj(adj A) = |A|n-2A



Inverse of 2x2 matrix

Math Meeting


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Inverse of 3x3 matrix
Math Meeting
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Matrix Inverse Properties
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slcmath@pc

Tuesday, May 3, 2016

XII - 11.12 Adjoint of a matrix - Video Lectures



XII - 11.12 Adjoint of a matrix - Video Lectures



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Exam Fear Videos


Adjoint of matrix order 2X2
FreeTutorialsWorld
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Adjoint of a 3x3 matrix
Astryl

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XII - 11.11 Singular matrix - Video Lectures


XII - 11.11 Singular matrix - Video Lectures

A square matrix is a singular matrix if its determinant is zero

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KhanAcademy

Monday, May 2, 2016

XII - 11.8 Transpose of a matrix - Video Lectures



XII -
11.8 Transpose of a matrix - Video Lectures


Tranpose of a matrix AT is obtained from A by changing its rows into columns and its columns into rows.
The first row of A is the first column of AT.

Properties of Transpose

1. (AT)T = A
2. (A+B) T = AT+BT ( A and B must have the same order)
3. (kA) T = kAT., (k is any scalar)
4. (AB) T = BTAT

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https://www.youtube.com/watch?v=uZYIZ5M2DaU
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Example Problem
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Ram Polepeddi

XII - 11.6 Subtraction of Matrices - Video Lectures




Class XII - Chapter Matrices

11.6 Subtraction of Matrices - Video Lectures


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numericalmethodsguy

XII - 11.7 Multiplication of matrices - Video Lectures


Class XII - Chapter Matrices

11.7 Multiplication of matrices - Video Lectures
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ProfRobBob


XII - 11.5 Multiplication of a matrix by a scalar - Video Lectures


Class XII - Chapter Matrices
11.5 Multiplication of a matrix by a scalar - Video Lectures

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ProfRobBob

Sunday, May 1, 2016

IIT JEE Mathematics Study Plan 11. Matrices

11.1 Matrix
11.2 Types of matrices
11.3 Equality of matrices
11.4 Algebra of matrices
11.5 Multiplication of a matrix by a scalar (scalar multiplication)
11.6 Subtraction of matrices (definition)
11.7 Multiplication of matrices
11.8 Transpose of a matrix
11.9 Symmetric and skew symmetric matrices
11.10 Determinants
11.11 Singular matrix
11.12 Adjoint of a matrix
11.13 Inverse of a matrix
11.14 elementary transformations of elementary operations of a matrix
11.15 Orthogonal matrix
11.16 Submatrix
11.17 Rank of a matrix
11.18 Some theorems on rank of a matrix
11.19 Equivalent matrices
11.20 Echelon form of a matrix
11.21 System of simultaneous linear equations
11.22 Solution of a non-homogeneous system of linear equations
11.23 Rank method
11.24 Solution of a homogeneous system of linear equations


Study Plan


Day 1

11.1 Matrix
11.2 Types of matrices
11.3 Equality of matrices
11.4 Algebra of matrices

Day 2

11.5 Multiplication of a matrix by a scalar (scalar multiplication)
11.6 Subtraction of matrices (definition)
11.7 Multiplication of matrices

Day 3
11.8 Transpose of a matrix
Objective Types questins 1 to 6,
Practice Exercises 1 to 10

Day 4

11.9 Symmetric and skew symmetric matrices
Ex 1 to 8


Day 5

11.10 Determinants
11.11 Singular matrix
11.12 Adjoint of a matrix

Day 6

11.13 Inverse of a matrix
11.14 elementary transformations of elementary operations of a matrix

Day 7
11.15 Orthogonal matrix
11.16 Submatrix
11.17 Rank of a matrix
11.18 Some theorems on rank of a matrix

Day 8
11.19 Equivalent matrices
11.20 Echelon form of a matrix
Objective Type Exercises 8 to 20

Day 9
11.21 System of simultaneous linear equations
11.22 Solution of a non-homogeneous system of linear equations
11.23 Rank method


Day 10

11.24 Solution of a homogeneous system of linear equations
Revision of concepts in the chapter



Day 11
OTE 21 to 40

Day 12
OTE 41 to 60

Day 13
OTE 61 to 80

Day 14
OTE 81 to 91
Fill in the blanks 1 to 17

Day 15

True/false questions 1 to 30



Day 16
Practice Exercises 11 to 20

Day 17
Practice Exercises 21 to 33


Day 18
Revision - Theory, Formulas and Difficult Problems

Day 19
Revision - Theory, Formulas and Difficult Problems


Day 20
Revision - Theory, Formulas and Difficult Problems


Updated 1 May 2016,  7 Nov 2008









Tuesday, December 9, 2008

Matrix – Definition

Matrix is a set of mn numbers (real or imaginary) arranged in the form a rectangular array of m rows and n columns. It is called an m×n matrix and is read ‘m by b matrix’.




Concepts

1. A matrix is a rectangular array of numbers [aij]
2. A matrix with m rows and n columns is called an m×n matrix and the size or dimension of this matrix is said to be m×n.
3. Two matrices are said to be equal provided they are of the same dimension and corresponding elements of the two matrices are equal.
4. A matrix is termed as square matrix if m = n or its size is m×m.

Types of matrices

Row matrix
Column matrix
Diagonal matrix
Scalar matrix
Identity or unit matrix
Upper triangular matrix
Lower triangular matrix





5. A matrix is termed as row matrix if m = 1
6. A matrix is termed as column matrix if n = 1
7. A matrix is termed as null or zero matrix if aij = 0 for all i and j.
8. A matrix is termed as diagonal matrix if aij = 0 for all ij where i is not equal to j.
9. A matrix is termed as scalar matrix if aij = 0 for all ij where i is not equal to j and aij = constant (k) for all i and j.
10. A matrix is termed as identity matrix or unit matrix if aij = 0 for all ij where i is not equal to j and aij = 1 for all i and j.

Equality of matrices

Two matrices

A is an m × n matrix [aij]

B is an r × s matrix [bij]

A and B are equal if

i. m= r (number of rows are same)
ii. n = s (number of columns are same)
iii. aij = bij for I =1,2,…,m abd j = 1,2,…,n

Algebra of Matrices

Addition of matrices

If two matrices are of the same order m x n, then their sum is a matrix of order m x n and is obtained by adding the corresponding elements.

(A+B)ij = aij + bij

Multiplication of a matrix by a scalar

kA = [kaij]m x n

Subtraction of matrices

A – B = A +(-B)

Multiplication of matrices

Two matrices A and B are conformable for multiplication if the number of columns in A is same as the number of rows in B.

A is premultiplier matrix and B is called post multiplier matrix.

AB is defined in the following way.

(AB) ij = Σ(r= 1 to n) airbrj
= ai1b1j+ai2b2j+…aimbmj

When AB exists, BA may or may not exist.

Properties of matrix multiplication

1. Matrix multiplication is not commutative in general.
2. Matrix multiplication is associative.
3. Matrix multiplication is distributive over matrix.
4. If A is an m x n matrix, then ImA = A = AIn
5. The product of two matrices can be the null matrix while neither of them is the null matrix.
6. Product of the matrix with a null matrix is always a null matrix.
7. If AB = 0 when either of them is not zero, it does not imply BA is zero.


Positive integral powers of A
An+1 = AnA
(Am)n = (A-)mn


Matrix polynomial = a0An+a1An-1+…+an-1A+anIn.

Traspose of a matrix

Tranpose of a matrix AT is obtained from A by changing its rows into columns and its columns into rows.
The first row of A is the first column of AT.

Properties of Transpose

1. (AT)T = A
2. (A+B) T = AT+BT ( A and B must have the same order)
3. (kA) T = kAT., (k is any scalar)
4. (AB) T = BTAT

Symmetric and skew symmetric matrices

Symmetric matrix

A square matrix is called a symmetric matrix iff aij = aji for all I,j.
It means (A)ij = (AT) ij

skew symmetric matrix
A square matrix is called a skew-symmetric matrix iff aij = -aji for all I,j.
It means (A)ij = -(AT) ij
It means AT = -A

Determinant of a matrix

Every square matrix can be associated to an expression or a number which is known as determinant.

If the matrix has only one element a11 then a11 is the determinant.

If the matrix is of order 2 that 2 by 2 matrix

|A| =

|a11 a12|
|a21 a22| =

a11*a22 – a12*a21

Determinant of a square matrix of order 3

Determinant of a square matrix of order 3 is the sum of the product of elements a1j in the first row with (-1) 1+j times the determinant of a 2×2 sub-matrix obtained by leaving the first row and column passing through the element.



(i) Only square matrices have determinants.
(ii) The determinant of a square matrix of order three can be expanded along any row or column.

Determinant of a square matrix of order 4 or more

(iii) Determinant of a square matrix of order 4 or more can be determined following the procedure of finding the determinant of a square matrix of order 3. But in this case, especially in the case of 4×4 matrix, when we omit the rows and columns containing the elements of a row, we get 3×3 sub-matrices and we have to find determinants for them.