Matrices
and System of
Linear Equations
 DHRUV MISTRY 160280106055
 DHRUVIL CHAVDA 160280106015
 SAVAN BARIA 160280106005
 DHARMIK DAVE 160280106022
 YASH JANI 160280106037
 ATRI BHATT 160280106007
 CHIRAG 160280106051
 VEDANT 160280106047
 YASH JAIN 160280106034
 AKHIL 160280106059
 SANDEEP 160280106046
INTRODUCTION
• Definition
A matrix is a rectangular array of elements or
entries aij involving m rows and n columns
  nmij
ijiii
j
j
j
a
aaaa
aaaa
aaaa
aaaa
A 























321
3333231
2232221
1131211 Rows, m
Columns, n
INTRODUCTION
• Definition
i. 2 matrices and
are said to be equal iff m = r and n = s then A
= B.
ii. If aij for i = j, then the entries a11,a22,a33,…
are called the diagonal of matrix A
  nmij MaA    nmij MbB 
TYPES OF MATRICES
Square Matrix
Matrix with order n x n
33
987
654
321
43
21


















 BA
nm
TYPES OF MATRICES
Diagonal Matrix
Matrix with order n x n with aij ≠ 0 and aij = 0
for i ≠ j











200
010
001
A
TYPES OF MATRICES
Scalar Matrix
A diagonal matrix in which the diagonal
elements are equal, aii = k and aij = 0 for i ≠ j
where k is a scalar
2,
100
010
001
2
200
020
002






















 kA
TYPES OF MATRICES
Identity Matrix
A diagonal matrix in which the diagonal
elements are ‘1’, aii = 1 and aij ≠ 0 for i ≠ j


















10
01
100
010
001
BA
TYPES OF MATRICES
Zero Matrix
A matrix which contains only zero elements,
aij = 0


















00
00
000
000
000
BA
TYPES OF MATRICES
Negative Matrix
A negative matrix of A =[aij] denoted by –A
where -A =[-aij]

























164
300
201
164
300
201
AA
TYPES OF MATRICES
Upper Triangular Matrix
If every elements below the diagonal is zero or
aij = 0, i > j











100
310
221
A
DIAGONAL
TYPES OF MATRICES
Lower Triangular Matrix
If every elements above the diagonal is zero or
aij = 0, i < j











143
012
001
A
DIAGONAL
TYPES OF MATRICES
Transpose of Matrix
If A =[aij] is an m x n matrix, then the
transpose of A, AT =[aij]T is the n x m matrix
defined by [aij] = [aji]T









 












152
411
321
143
512
211
T
AA
TYPES OF MATRICES
Properties Transposition Operation
• Let A and B matrices and k, . Then,
 
 
  TTT
TT
TT
BABAiii
kAkAii
AAi



)
)
)
Rk 
TYPES OF MATRICES
Example 1:
• If and , find
 
 
 T
T
T
ABiii
Bii
Ai
)
2)
)









254
321
A











2
3
1
B
TYPES OF MATRICES
Answer 1:
 
   
   231)
4622)
2
5
4
3
2
1
)













T
T
T
ABiii
Bii
Ai
TYPES OF MATRICES
Symmetric Matrix
If AT = A, where the elements obey the rule
aij = aji
























324
221
415
324
221
415
T
AA
TYPES OF MATRICES
Skew Symmetric Matrix
If AT = - A, where the elements obey the rule
aij = - aji, so that the diagonal must contain
zeroes.














074
701
410
A
TYPES OF MATRICES
Skew Symmetric Matrix
AA
A
T











































074
701
410
074
701
410
074
701
410
TYPES OF MATRICES
Row Echelon Form (REF)
Matrix A is said to be in REF if it satisfies the
following properties:
• Rows consisting entirely zeroes occur at the bottom of the
matrix.
• For each row that doesn’t consist entirely of zeroes, the 1st
nonzero is 1.
• For each non zero row, number 1 appear to the right of the
leading 1 of the previous row.
TYPES OF MATRICES




















 

100
310
421
000
710
411
B
A
LEADING 1
ZERO ROW AT THE BOTTOM
LEADING 1
TYPES OF MATRICES
Reduced Row Echelon Form (RREF)
Matrix A is said to be in REF if it satisfies the
following properties:
• Rows consisting entirely zeroes occur at the bottom of the
matrix.
• For each row that doesn’t consist entirely of zeroes, the 1st
nonzero is 1.
• For each non zero row, number 1 appear to the right of the
leading 1 of the previous row.
• If a column contains a leading 1, then all other entries in
the column are zero
TYPES OF MATRICES




















 

100
010
001
000
710
401
B
A
LEADING 1
ZERO ROW AT THE BOTTOM
LEADING 1
Types of Solutions
Consistent System
One solution
Consistent System
Infinite solutions
Inconsistent System
No solution
A linear equation is an equation that can be written in the form:
The coefficients ai and the constant b can be real or complex numbers.
A Linear System is a collection of one or more linear equations in the
same variables. Here are a few examples of linear systems:
bxaxaxa nn2211  
4z2y2x
2zy3x2
1zyx



4xx4x
2xxx2x
1xx2x
532
5432
421



1zy2x
7z7y4x3


Any system of linear equations can be put into matrix form: bxA


The matrix A contains the coefficients of the variables, and the vector x has
the variables as its components.
For example, for the first system above the matrix version would be:
 
bxA
4
2
1
z
y
x
221
132
111
  


































Prepared by Vince Zaccone
For Campus Learning Assistance
Services at UCSB
Here is the next system. The basic pattern is to start at the upper left corner, then use row
operations to get zeroes below, then work counterclockwise until the matrix is in REF.


































3
0
1
310
310
111
RRR
R2RR
4
2
1
221
132
111
4z2y2x
2zy3x2
1zyx
13
*
3
12
*
2























3
0
1
000
310
111
RRR3
0
1
310
310
111
23
*
3
At this point you might notice a problem. That last row doesn’t make sense. It might help to
write out the equation that the last row represents.
It says 0x+0y+0z=3.
Are there any values of x, y and z that make this equation work? (the answer is NO!)
This system is called INCONSISTENT because we arrive at a contradiction during the
solution procedure. This means that the system has no solution.
This line is the
intersection of a pair of
the planes
This line is the intersection
of a different pair of the
planes
Prepared by Vince Zaccone
For Campus Learning Assistance
Services at UCSB
No Solution
If the system is inconsistent there will be no solutions.
In this case there will be a contradiction that appears
during the solution process.
This is the reduced matrix (actually we could go one step further and get a
zero up in row 1). Notice that we got a row of zeroes in the left part of the
augmented matrix. When this happens the system will either be inconsistent,
like this one, or we will have a free variable (infinite # of solutions).
4z2y2x
2zy3x2
1zyx














3
0
1
000
310
111
Consistent or Inconsistent System?
2100
5010
1001
𝑦 + 3𝑧 = 2
𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟
2000
7010
4001
0000
2310
2501 𝑥 + 5𝑧 = 2
(𝑥 = 2 − 5𝑧, 𝑦 = 2 − 3𝑧, 𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟)
𝑦 = 5
𝑧 = 2
𝑥 = 1
𝑦 = 7
0 = 2
𝑥 = 4
𝑁𝑜 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛: 𝐼𝑛𝑐𝑜𝑛𝑠𝑖𝑠𝑡𝑒𝑛𝑡 𝑠𝑦𝑠𝑡𝑒𝑚
𝐼𝑛𝑓𝑖𝑛𝑖𝑡𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠: 𝐶𝑜𝑛𝑠𝑖𝑠𝑡𝑒𝑛𝑡 𝑠𝑦𝑠𝑡𝑒𝑚
{(𝑥, 𝑦, 𝑧)|𝑥 = 2 − 5𝑧, 𝑦 = 2 − 3𝑧, 𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟}
𝑜𝑟
Inverse Matrix Method
Given a set of linear equations
x + 2y = 4
3x − 5y = 1
It can be written in matrix form as…
=
AX = B
This is the matrix form of the linear equations
1 2
3 −5( ) x
y( ) 4
1( )
Given that…
AX = B
A-1AX = A-1B
(A−1A = I, the identity matrix and multiplying any matrix
by I leaves the matrix unchanged)
X = A−1B
Thank
You

Matrices and System of Linear Equations ppt

  • 1.
  • 2.
     DHRUV MISTRY160280106055  DHRUVIL CHAVDA 160280106015  SAVAN BARIA 160280106005  DHARMIK DAVE 160280106022  YASH JANI 160280106037  ATRI BHATT 160280106007  CHIRAG 160280106051  VEDANT 160280106047  YASH JAIN 160280106034  AKHIL 160280106059  SANDEEP 160280106046
  • 3.
    INTRODUCTION • Definition A matrixis a rectangular array of elements or entries aij involving m rows and n columns   nmij ijiii j j j a aaaa aaaa aaaa aaaa A                         321 3333231 2232221 1131211 Rows, m Columns, n
  • 4.
    INTRODUCTION • Definition i. 2matrices and are said to be equal iff m = r and n = s then A = B. ii. If aij for i = j, then the entries a11,a22,a33,… are called the diagonal of matrix A   nmij MaA    nmij MbB 
  • 5.
    TYPES OF MATRICES SquareMatrix Matrix with order n x n 33 987 654 321 43 21                    BA nm
  • 6.
    TYPES OF MATRICES DiagonalMatrix Matrix with order n x n with aij ≠ 0 and aij = 0 for i ≠ j            200 010 001 A
  • 7.
    TYPES OF MATRICES ScalarMatrix A diagonal matrix in which the diagonal elements are equal, aii = k and aij = 0 for i ≠ j where k is a scalar 2, 100 010 001 2 200 020 002                        kA
  • 8.
    TYPES OF MATRICES IdentityMatrix A diagonal matrix in which the diagonal elements are ‘1’, aii = 1 and aij ≠ 0 for i ≠ j                   10 01 100 010 001 BA
  • 9.
    TYPES OF MATRICES ZeroMatrix A matrix which contains only zero elements, aij = 0                   00 00 000 000 000 BA
  • 10.
    TYPES OF MATRICES NegativeMatrix A negative matrix of A =[aij] denoted by –A where -A =[-aij]                          164 300 201 164 300 201 AA
  • 11.
    TYPES OF MATRICES UpperTriangular Matrix If every elements below the diagonal is zero or aij = 0, i > j            100 310 221 A DIAGONAL
  • 12.
    TYPES OF MATRICES LowerTriangular Matrix If every elements above the diagonal is zero or aij = 0, i < j            143 012 001 A DIAGONAL
  • 13.
    TYPES OF MATRICES Transposeof Matrix If A =[aij] is an m x n matrix, then the transpose of A, AT =[aij]T is the n x m matrix defined by [aij] = [aji]T                        152 411 321 143 512 211 T AA
  • 14.
    TYPES OF MATRICES PropertiesTransposition Operation • Let A and B matrices and k, . Then,       TTT TT TT BABAiii kAkAii AAi    ) ) ) Rk 
  • 15.
    TYPES OF MATRICES Example1: • If and , find      T T T ABiii Bii Ai ) 2) )          254 321 A            2 3 1 B
  • 16.
    TYPES OF MATRICES Answer1:          231) 4622) 2 5 4 3 2 1 )              T T T ABiii Bii Ai
  • 17.
    TYPES OF MATRICES SymmetricMatrix If AT = A, where the elements obey the rule aij = aji                         324 221 415 324 221 415 T AA
  • 18.
    TYPES OF MATRICES SkewSymmetric Matrix If AT = - A, where the elements obey the rule aij = - aji, so that the diagonal must contain zeroes.               074 701 410 A
  • 19.
    TYPES OF MATRICES SkewSymmetric Matrix AA A T                                            074 701 410 074 701 410 074 701 410
  • 20.
    TYPES OF MATRICES RowEchelon Form (REF) Matrix A is said to be in REF if it satisfies the following properties: • Rows consisting entirely zeroes occur at the bottom of the matrix. • For each row that doesn’t consist entirely of zeroes, the 1st nonzero is 1. • For each non zero row, number 1 appear to the right of the leading 1 of the previous row.
  • 21.
    TYPES OF MATRICES                       100 310 421 000 710 411 B A LEADING 1 ZERO ROW AT THE BOTTOM LEADING 1
  • 22.
    TYPES OF MATRICES ReducedRow Echelon Form (RREF) Matrix A is said to be in REF if it satisfies the following properties: • Rows consisting entirely zeroes occur at the bottom of the matrix. • For each row that doesn’t consist entirely of zeroes, the 1st nonzero is 1. • For each non zero row, number 1 appear to the right of the leading 1 of the previous row. • If a column contains a leading 1, then all other entries in the column are zero
  • 23.
    TYPES OF MATRICES                       100 010 001 000 710 401 B A LEADING 1 ZERO ROW AT THE BOTTOM LEADING 1
  • 24.
    Types of Solutions ConsistentSystem One solution Consistent System Infinite solutions Inconsistent System No solution
  • 25.
    A linear equationis an equation that can be written in the form: The coefficients ai and the constant b can be real or complex numbers. A Linear System is a collection of one or more linear equations in the same variables. Here are a few examples of linear systems: bxaxaxa nn2211   4z2y2x 2zy3x2 1zyx    4xx4x 2xxx2x 1xx2x 532 5432 421    1zy2x 7z7y4x3   Any system of linear equations can be put into matrix form: bxA   The matrix A contains the coefficients of the variables, and the vector x has the variables as its components. For example, for the first system above the matrix version would be:   bxA 4 2 1 z y x 221 132 111                                     
  • 26.
    Prepared by VinceZaccone For Campus Learning Assistance Services at UCSB Here is the next system. The basic pattern is to start at the upper left corner, then use row operations to get zeroes below, then work counterclockwise until the matrix is in REF.                                   3 0 1 310 310 111 RRR R2RR 4 2 1 221 132 111 4z2y2x 2zy3x2 1zyx 13 * 3 12 * 2                        3 0 1 000 310 111 RRR3 0 1 310 310 111 23 * 3 At this point you might notice a problem. That last row doesn’t make sense. It might help to write out the equation that the last row represents. It says 0x+0y+0z=3. Are there any values of x, y and z that make this equation work? (the answer is NO!) This system is called INCONSISTENT because we arrive at a contradiction during the solution procedure. This means that the system has no solution.
  • 27.
    This line isthe intersection of a pair of the planes This line is the intersection of a different pair of the planes Prepared by Vince Zaccone For Campus Learning Assistance Services at UCSB No Solution If the system is inconsistent there will be no solutions. In this case there will be a contradiction that appears during the solution process. This is the reduced matrix (actually we could go one step further and get a zero up in row 1). Notice that we got a row of zeroes in the left part of the augmented matrix. When this happens the system will either be inconsistent, like this one, or we will have a free variable (infinite # of solutions). 4z2y2x 2zy3x2 1zyx               3 0 1 000 310 111
  • 28.
    Consistent or InconsistentSystem? 2100 5010 1001 𝑦 + 3𝑧 = 2 𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟 2000 7010 4001 0000 2310 2501 𝑥 + 5𝑧 = 2 (𝑥 = 2 − 5𝑧, 𝑦 = 2 − 3𝑧, 𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟) 𝑦 = 5 𝑧 = 2 𝑥 = 1 𝑦 = 7 0 = 2 𝑥 = 4 𝑁𝑜 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛: 𝐼𝑛𝑐𝑜𝑛𝑠𝑖𝑠𝑡𝑒𝑛𝑡 𝑠𝑦𝑠𝑡𝑒𝑚 𝐼𝑛𝑓𝑖𝑛𝑖𝑡𝑒 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛𝑠: 𝐶𝑜𝑛𝑠𝑖𝑠𝑡𝑒𝑛𝑡 𝑠𝑦𝑠𝑡𝑒𝑚 {(𝑥, 𝑦, 𝑧)|𝑥 = 2 − 5𝑧, 𝑦 = 2 − 3𝑧, 𝑧 = 𝑎𝑛𝑦 𝑟𝑒𝑎𝑙 𝑛𝑢𝑚𝑏𝑒𝑟} 𝑜𝑟
  • 29.
    Inverse Matrix Method Givena set of linear equations x + 2y = 4 3x − 5y = 1 It can be written in matrix form as… = AX = B This is the matrix form of the linear equations 1 2 3 −5( ) x y( ) 4 1( )
  • 30.
    Given that… AX =B A-1AX = A-1B (A−1A = I, the identity matrix and multiplying any matrix by I leaves the matrix unchanged) X = A−1B
  • 31.