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12M03

Matrices

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Matrices

Sachin

Dhoni

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12MO3.1

Introduction to Matrices

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Learning Objectives

What is Matrix

Types of Matrices

Equality of Matrices

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12MO3.1

CV 1

What is Matrix

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Row

Column

Matrix Form

Matrix Form

 

 

 

 

GEETA

RAM

 

 

 

GEETA

RAM

Pen

Pencil

Book

 

 

 

 

 

 

GEETA

RAM

Pen

Pencil

Book

 

 

 

 

 

 

 

 

 

Total no. of Rows

Total no. of Rows

Total no. of Columns

 

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Sol.

 

 

 

 

 

 

 

 

 

Row

Column

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Order of the Matrices

 

 

 

 

 

 

 

 

 

 

 

Multiplication of total no. of rows and columns

 

 

 

 

 

 

 

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Position of the elements

 

Total no. of elements

Unique position

Row’s number and Column’s number

Ex.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ex

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Sol.

 

 

 

 

 

 

 

(iii)

 

 

 

 

 

 

 

 

 

 

 

 

 

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Sol.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Required Matrix=

 

 

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12MO3.1

CV 2

Types of Matrices

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Types of Matrices

Column Matrix

Row Matrix

Square Matrix

Diagonal Matrix

Scalar Matrix

0

Identity Matrix

Zero Matrix

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Column Matrix

Matrix which contains only one column.

 

 

 

 

 

 

 

 

 

NO

?

 

 

 

 

 

 

 

Column Matrix

Column Matrix

,It is a column matrix.

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Row Matrix

Matrix which contains only one row.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NO

?

Row Matrix

Row Matrix

,it is a row matrix.

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Square Matrix

Matrix which contains equal number of rows and columns.

 

 

 

 

 

 

 

 

 

 

 

Square Matrix

Square Matrix

 

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Diagonal Matrix

 

 

 

 

 

 

 

 

 

 

 

 

Diagonal elements

 

Diagonal element

Square Matrix

 

 

 

 

 

 

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Diagonal Matrix

Square matrix which has all non diagonal elements zero.

 

 

 

Diagonal Matrix

Diagonal elements

 

 

 

 

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Scalar Matrix

 

 

 

 

Diagonal elements

 

 

Diagonal matrix

Scalar matrix

Special Case

Diagonal matrix whose all diagonal elements are equal.

Equal

 

 

Scalar matrix

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Identity Matrix

 

 

 

 

Diagonal elements

 

 

Diagonal matrix

Scalar matrix

Special Case

 

Equal

 

 

Identity matrix

 

Special Case

Identity matrix

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Zero Matrix or Null Matrix

Matrix whose all elements are 0.

 

 

 

 

 

 

 

 

 

Zero Matrix

Zero Matrix

No

?

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Q. Mark the correct type.

Matrices

Square

Matrix

Diagonal

Matrix

Scalar

Matrix

Identity

Matrix

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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12MO3.1

CV 3

Equality of Matrices

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Equal Matrices

Two matrices are equal if they have

(i) Same order

(ii) All corresponding elements equal

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Q . Find the values of x, y and z from the following equations:�

 

 

Sol.

Both matrices are equal.

All corresponding elements should be equal.

 

 

 

 

 

 

 

 

 

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Sol.

Both are equal matrices

All corresponding elements should be equal.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Learning Objectives

Addition of Matrices?

Scalar Multiplication of a Matrix

Difference of Matrices

Multiplication of a Matrices

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12MO3.1

CV 3

Addition of Matrices

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Addition of Matrices

Room A

Boys

Girls

Room B

Boys

Girls

Room A + Room B

Boys

Girls

Merged

Matrix form

 

 

 

 

 

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Q .

Sol .

 

 

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Q.) Compute the following:

 

 

Sol.

 

 

 

Addition of corresponding elements

 

 

 

 

‘’

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Commutative Law of Matrix Addition-

 

 

Proof.

 

 

 

 

 

 

 

 

 

 

EQUAL

 

Proved

 

 

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Total no. of rows

Total no. of columns

 

 

Corresponding

element

Corresponding

row

Corresponding

column

Total no. of rows

Total no. of columns

 

 

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Associative property of Addition-

 

 

Proof.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

EQUAL

Proved

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12MO3.2

CV 4

Scalar multiplication of Matrices

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Ex

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Scalar Multiplication of Matrices-

Room A

Boys

Girls

Room A

Boys

Girls

Doubled

Matrix form=

 

Multiplication of each element of Matrix by the scalar.

 

Multiplication of each element of Matrix by the 2.

 

Scalar

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Ex.

 

 

 

 

 

 

 

 

 

 

 

 

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Properties Of Scalar Multiplication of Matrices-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Properties Of Scalar Multiplication of Matrices-

 

 

 

 

 

 

 

 

 

 

 

 

Equal

 

Proved

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Negative of a Matrix-

Negating each element of Matrix.

 

 

 

 

 

Negative of Matrix A is denoted by –A .

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Additive identity existence-

Proof.

 

 

 

 

 

 

 

 

Equal

Proved

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Additive inverse existence-

 

 

 

Proof.

 

 

 

 

 

 

 

Zero Matrix

Proved

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12MO3.1

CV 5

Difference of Matrices

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Difference of Matrices

Subtraction of corresponding elements of matrices

Same order

 

 

 

 

 

 

 

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A-B=?

 

 

 

 

 

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Sol.

 

 

 

 

 

 

 

 

 

 

 

Q.

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12MO3.1

CV 6

Multiplication of Matrices

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GEETA

RAM

Pencil

Book

 

 

 

 

Cost

Book

Pencil

 

 

Items

 

 

Matrix Form

Requirements

Cost

 

 

Money needed

 

 

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GEETA

RAM

Pencil

Book

 

 

 

 

Cost shop 1

Book

Pencil

 

 

Items

Matrix Form

Requirements

Cost

 

 

Money needed

Cost shop 2

 

 

 

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Requirements

Cost

 

 

Money spent

 

 

2 Columns

2 Rows

 

 

 

 

Requirements

Cost

 

 

Money spent

 

 

 

 

 

 

 

 

 

 

 

2 C

 

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Sol.

 

 

 

 

Yes

 

 

 

 

No

 

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Q. Compute the indicated products.

 

Sol.

 

 

 

Required products

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Properties of Matrix Multiplication-

Associative Law-

 

Proof-

 

 

 

 

 

 

 

 

 

 

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Properties of Matrix Multiplication-

Distributive Law-

 

Proof-

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Properties of Matrix Multiplication-

Multiplicative Identity Law-

Proof-

 

Identity Matrix

Square Matrix have identity matrix of

same order such that

Square Matrix

 

 

 

 

 

 

 

Proved

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12MO3.1

CV 7

Transpose of a Matrix

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Transpose of a Matrix-

Interchanging rows with columns of corresponding matrix or vice versa.

 

Sol.

 

 

Ex.

 

 

 

 

 

 

 

 

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Q.) Find the transpose of a Matrix given below.

 

Sol.

 

 

 

 

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Properties of transpose of a matrix-

 

Proof.

 

 

 

 

Proved

Equal

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Properties of transpose of a matrix-

 

Proof.

 

 

 

 

 

 

1

0

Proved

Equal

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Properties of transpose of a matrix-

 

Proof.

 

 

 

 

Proved

 

 

 

 

 

 

Equal

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Properties of transpose of a matrix-

 

Proof.

 

 

 

 

 

 

 

 

 

 

 

 

Equal

Proved

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12MO3.1

CV 8

Symmetric and Skew Symmetric Matrix

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Symmetric Matrix-

Square Matrix which is equal to its transpose.

 

 

Ex.

 

Equal

 

Symmetric Matrix

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Skew Symmetric Matrix-

Square Matrix whose transpose is equal to its negative .

 

 

Ex.

 

Equal

 

Skew Symmetric Matrix

 

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Proof

 

 

 

 

 

 

 

 

Equal

 

Proved

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Proof

 

 

 

 

 

 

 

 

Equal

 

Proved

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Theorem 2-

Any square Matrix can be expressed as sum of Symmetric

and Skew Symmetric Matrix.

 

Symmetric Matrix

Skew Symmetric Matrix

 

 

 

 

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Q. Find Skew - symmetric matrix of given below

 

 

Sol.

 

 

 

 

 

 

 

 

 

 

 

 

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12MO3.1

CV 9

Elementary Operation of Matrices

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Elementary Operation of Matrices-

 

 

 

 

 

 

 

 

Interchanging of any two rows

 

 

 

 

 

 

 

 

Ex.

 

 

 

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Interchanging of any two columns

 

 

 

 

 

Ex.

 

 

 

 

 

 

 

 

 

 

 

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Multiplication of elements of any row by number

 

 

 

 

 

Ex

 

 

 

 

 

 

Any non-zero number

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Multiplication of elements of any column by number

 

 

Ex

Any non-zero number

 

 

 

 

 

 

 

 

 

 

 

S

 

 

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Addition or subtraction of elements of any row to the corresponding element of any other row multiplied by a number.

 

 

Non-zero number

 

 

 

 

 

 

 

Ex

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Addition or subtraction of elements of any column to the corresponding element of any other column multiplied by a number.

 

 

Non-zero number

 

 

 

Ex-

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12MO3.1

CV 10

Invertible Matrices

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Invertible Matrices-

 

 

 

 

 

Identity Matrix

 

 

Non-Diagonal element

Ex.

 

 

 

 

 

 

Identity Matrix

 

 

 

 

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Inverse of Matrix by Elementary Operation-

 

Multiplicative Identity

On applying elementary operations on LHS and RHS

LHS

R.H.S.

 

Inverse of A

 

LHS

 

On applying elementary operation if any row or column has

all elements zero then inverse does not exists.

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Ex.

Find inverse of matrix

 

Sol.

 

Multiplicative inverse

 

 

 

 

 

 

 

 

 

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Ex.

Find inverse of matrix

 

 

Sol.

Multiplicative inverse

 

 

 

 

 

 

 

 

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Inverse of a matrix is unique.

Proof .

 

 

 

Identity Matrix

 

 

Identity Matrix

 

 

 

 

Multiplicative Identity

Associative Law

 

Multiplicative Identity

To Prove

 

Proved

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Inverse of a matrix is unique.

Proof .

 

 

 

Identity Matrix

 

 

Identity Matrix

 

 

 

 

Multiplicative Identity

Associative Law

 

Multiplicative Identity

To Prove

 

Proved

A and B are invertible matrices of same order.