Matrices and Vectors

Matrix

( 1 3 3 2 1 3 9 -6 4 3 2 6 -4 2 2 )

column matrices

( 3 9 6 ) ( 3 -6 -4 ) ( 2 4 2 ) ( 1 3 2 )

row matrices

( 3 3 2 1 ) ( 9 -6 4 3 ) ( 6 -4 2 2 )
( 5 -8 1 3 -5 1 -4 7 -1 ) ( 2 1 3 1 1 2 -1 3 1 )
( 5 0 0 3 -5 0 -4 7 -1 ) ( 0 1 3 0 1 2 0 0 1 )
( 5 0 0 0 -5 0 0 0 -1 ) ( -3 0 0 0 -3 0 0 0 -3 ) ( 1 0 0 0 1 0 0 0 1 )

Representing SLE

Standard form

x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 3x1 + 9 x2 - 6 x3 + 4 x4 + 3 x5 = -7 2 x1 + 6 x2 - 4 x3 + 2 x4 + 2 x5 = -4

Augmented Matrix

( 1 3 3 2 1 7 3 9 -6 4 3 -7 2 6 -4 2 2 -4 )

Vector representation

( 1 3 2 ) x1 + ( 3 9 6 ) x2 + ( 3 -6 -4 ) x3 + ( 2 4 2 ) x4 + ( 1 3 2 ) x5 = ( 7 -7 -4 )

Matrix Representation

( 1 3 3 2 1 3 9 -6 4 3 2 6 -4 2 2 ) ( x1 x2 x3 x4 x5 ) = ( 7 -7 -4 )

Matrix Representation

( 1 3 3 2 1 3 9 -6 4 3 2 6 -4 2 2 ) x = ( 7 -7 -4 )

Gauss Method

Example 01

{ x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 3x1 + 9 x2 - 6 x3 + 4 x4 + 3 x5 = -7 2 x1 + 6 x2 - 4 x3 + 2 x4 + 2 x5 = -4 ρ2 = -3ρ1 +ρ2 { x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 2 x1 + 6 x2 - 4 x3 + 2 x4 + 2 x5 = -4
( 1 0 0 -3 1 0 0 0 1 ) ( 1 3 3 2 1 7 3 9 -6 4 3 -7 2 6 -4 2 2 -4 ) =( 1 3 3 2 1 9 0 0 -15 -2 0 -28 2 6 -4 2 2 -4 )
{ x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 2 x1 + 6 x2 - 4 x3 + 2 x4 + 2 x5 = -4 ρ3 = -2ρ1 +ρ3 { x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 -10 x3 -2 x4 = -18
( 1 0 0 0 1 0 -2 0 1 ) ( 1 3 3 2 1 7 0 0 -15 -2 0 -28 2 6 -4 2 2 -4 ) =( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 -10 -2 0 -18 )
{ x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 -10 x3 -2 x4 = -18 ρ3 = -23 ρ2 +ρ3 { x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 -23 x4 = 23
( 1 0 0 0 1 0 0 -23 1 ) ( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 -10 -2 0 -18 ) =( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 0 -23 0 23 )
{ x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 -23 x4 = 23 ρ3 = -32 ρ3 { x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 x4 = -1
( 1 0 0 0 1 0 0 0 -32 ) ( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 0 -23 0 23 ) =( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 0 1 0 -1 )
{ x1 + 3 x2 + 3 x3 + 2 x4 + x5 = 7 -15 x3 - 2 x4 = -28 x4 = -1 ρ1 = ρ1 -2 ρ3 { x1 + 3 x2 + 3 x3 + x5 = 9 -15 x3 - 2 x4 = -28 x4 = -1
( 1 0 -2 0 1 0 0 0 1 ) ( 1 3 3 2 1 7 0 0 -15 -2 0 -28 0 0 0 1 0 -1 ) =( 1 3 3 0 1 9 0 0 -15 -2 0 -28 0 0 0 1 0 -1 )
{ x1 + 3 x2 + 3 x3 + x5 = 9 -15 x3 - 2 x4 = -28 x4 = -1 ρ2 = ρ2 +2 ρ3 { x1 + 3 x2 + 3 x3 + x5 = 9 -15 x3 = -30 x4 = -1
( 1 0 0 0 1 2 0 0 1 ) ( 1 3 3 0 1 9 0 0 -15 -2 0 -28 0 0 0 1 0 -1 ) =( 1 3 3 0 1 9 0 0 -15 0 0 -30 0 0 0 1 0 -1 )
{ x1 + 3 x2 + 3 x3 + x5 = 9 -15 x3 = -30 x4 = -1 ρ2 = -115 ρ2 { x1 + 3 x2 + 3 x3 + x5 = 9 x3 = 2 x4 = -1
( 1 0 0 0 -115 0 0 0 1 ) ( 1 3 3 0 1 9 0 0 -15 0 0 -30 0 0 0 1 0 -1 ) =( 1 3 3 0 1 9 0 0 1 0 0 2 0 0 0 1 0 -1 )
{ x1 + 3 x2 + 3 x3 + x5 = 9 x3 = 2 x4 = -1 ρ1 = ρ1 -3 ρ2 { x1 + 3 x2 + x5 = 3 x3 = 2 x4 = -1
( 1 -3 0 0 1 0 0 0 1 ) ( 1 3 3 0 1 9 0 0 1 0 0 2 0 0 0 1 0 -1 ) =( 1 3 0 0 1 3 0 0 1 0 0 2 0 0 0 1 0 -1 )
x1 = 3 - 3 s1 - 3 s2 x2 = s1 x3 = 2 x4 = -1 x5 = s2 or { ( 3 0 2 -1 0 ) particular + ( -3 1 0 0 0 ) s1 + ( -1 0 0 0 1 ) s2 homogeneous s1 ,s2 }

Gauss Method

Example 02

{ x3 + 2 x4 = 3 x1 + 3 x2 + 3 x3 + 2 x4 = 1 2x1 + 6 x2 + 5 x3 + 2 x4 = 0 swap( ρ1 , ρ2 ) { x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 2x1 + 6 x2 + 5 x3 + 2 x4 = 0
( 0 1 0 1 0 0 0 0 1 ) ( 0 0 1 2 3 1 3 3 2 1 2 6 5 2 0 ) =( 1 3 3 2 1 0 0 1 2 3 2 6 5 2 0 )
{ x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 2x1 + 6 x2 + 5 x3 + 2 x4 = 0 ρ3 = ρ3 -2 ρ1 { x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 - x3 - 2 x4 = -2
( 1 0 0 0 1 0 -2 0 1 ) ( 1 3 3 2 1 0 0 1 2 3 2 6 5 2 0 ) =( 1 3 3 2 1 0 0 1 2 3 0 0 -1 -2 -2 )
{ x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 - x3 - 2 x4 = -2 ρ3 = ρ3 + ρ2 { x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 0 = 1
( 1 0 0 0 1 0 0 1 1 ) ( 1 3 3 2 1 0 0 1 2 3 0 0 -1 -2 -2 ) =( 1 3 3 2 1 0 0 1 2 3 0 0 0 0 1 )
{ x1 + 3 x2 + 3 x3 + 2 x4 = 1 x3 + 2 x4 = 3 0 = 1 ρ1 = ρ1 -3 ρ2 { x1 + 3 x2 - 4 x4 = -8 x3 + 2 x4 = 3 0 = 1
( 1 -3 0 0 1 0 0 0 1 ) ( 1 3 3 2 1 0 0 1 2 3 0 0 0 0 1 ) =( 1 3 0 -4 -8 0 0 1 2 3 0 0 0 0 1 )
{ x3 + 2 x4 = 5 x1 + 3 x2 + 3 x3 + 2 x4 = 3 2x1 + 6 x2 + 5 x3 + 2 x4 = 1 swap( ρ1 , ρ2 ) { x1 + 3 x2 + 3 x3 + 2 x4 = 3 x3 + 2 x4 = 5 2x1 + 6 x2 + 5 x3 + 2 x4 = 1
( 0 1 0 1 0 0 0 0 1 ) ( 0 0 1 2 5 1 3 3 2 3 2 6 5 2 1 ) =( 1 3 0 -4 a 0 0 1 2 b 0 0 0 0 c )
{ x3 + 2 x4 = 5 x1 + 3 x2 + 3 x3 + 2 x4 = 3 2x1 + 6 x2 + 5 x3 + 2 x4 = 1
( 1 -3 0 0 1 0 0 0 1 ) ( 1 0 0 0 1 0 0 1 1 ) ( 1 0 0 0 1 0 -2 0 1 ) ( 0 1 0 1 0 0 0 0 1 ) ( 5 A 3 1 ) =( 1 3 0 -4 a 0 0 1 2 b 0 0 0 0 c ) ( -3 1 0 1 0 0 1 -2 1 ) ( 0 0 1 2 5 1 3 3 2 3 2 6 5 2 1 ) =( 1 3 0 -4 a 0 0 1 2 b 0 0 0 0 c )

Gauss Method

2×2 inverse

{ 5 x1 + 4 x2 = 1 9x1 + 7 x2 = 0 { 5 x1 + 4 x2 = 0 9x1 + 7 x2 = 1
( 15 0 0 1 ) ( 5 4 1 0 9 7 0 1 ) =( 1 45 15 0 9 7 0 1 )
( 15 0 0 1 ) ( 5 4 1 0 9 7 0 1 ) =( 1 45 15 0 9 7 0 1 )
( 1 0 -9 1 ) ( 1 45 15 0 9 7 0 1 ) = ( 1 45 15 0 0 -15 -95 1 )
( 1 0 -9 1 ) ( 15 0 0 1 ) ( 5 4 1 0 9 7 0 1 ) = ( 1 45 15 0 0 -15 -95 1 )
( 1 0 0 -5 ) ( 1 45 15 0 0 -15 -95 1 ) = ( 1 45 15 0 0 1 9 -5 )
( 1 0 0 -5 ) ( 1 0 -9 1 ) ( 15 0 0 1 ) ( 5 4 1 0 9 7 0 1 ) = ( 1 45 15 0 0 1 9 -5 )
( 1 -45 0 1 ) ( 1 45 15 0 0 1 9 -5 ) = ( 1 0 -7 4 0 1 9 -5 )
( 1 -45 0 1 ) ( 1 0 0 -5 ) ( 1 0 -9 1 ) ( 15 0 0 1 ) B ( 5 4 1 0 9 7 0 1 ) (A|I) = ( 1 0 7 -4 0 1 -9 5 ) (BA|BI)

Gauss Method

3×3 inverse

{ - x2 + x3 = 1 2x1 + 3 x2 - 2 x3 = 0 x1 + 2 x2 - x3 = 0 { - x2 + x3 = 0 2x1 + 3 x2 - 2 x3 = 1 x1 + 2 x2 - x3 = 0 { - x2 + x3 = 0 2x1 + 3 x2 - 2 x3 = 0 x1 + 2 x2 - x3 = 1
( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 )
( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) swap( ρ1 , ρ3 ) ( 1 2 -1 0 0 1 2 3 -2 0 1 0 0 -1 1 1 0 0 )
( 0 0 1 0 1 0 1 0 0 ) B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 2 -1 0 0 1 2 3 -2 0 1 0 0 -1 1 1 0 0 ) (BA|BI)
( 1 2 -1 0 0 1 2 3 -2 0 1 0 0 -1 1 1 0 0 ) ρ2 = ρ2 -2ρ1 ( 1 2 -1 0 0 1 0 -1 0 0 1 -2 0 -1 1 1 0 0 )
( 1 0 0 -2 1 0 0 0 1 ) E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 2 -1 0 0 1 0 -1 0 0 1 -2 0 -1 1 1 0 0 ) (BA|BI)
( 1 2 -1 0 0 1 0 -1 0 0 1 -2 0 -1 1 1 0 0 ) ρ2 = -ρ2 ( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 -1 1 1 0 0 )
( 1 0 0 0 -1 0 0 0 1 ) E2 E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 -1 1 1 0 0 ) (BA|BI)
( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 -1 1 1 0 0 ) ρ3 = ρ3 +ρ2 ( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 0 1 1 -1 2 )
( 1 0 0 0 1 0 0 1 1 ) E3 E2 E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 0 1 1 -1 2 ) (BA|BI)
( 1 2 -1 0 0 1 0 1 0 0 -1 2 0 0 1 1 -1 2 ) ρ1 = ρ1 +ρ3 ( 1 2 0 1 -1 3 0 1 0 0 -1 2 0 0 1 1 -1 2 )
( 1 0 1 0 1 0 0 0 1 ) E4 E3 E2 E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 2 0 1 -1 3 0 1 0 0 -1 2 0 0 1 1 -1 2 ) (BA|BI)
( 1 2 0 1 -1 3 0 1 0 0 -1 2 0 0 1 1 -1 2 ) ρ1 = ρ1 -2ρ2 ( 1 0 0 1 1 -1 0 1 0 0 -1 2 0 0 1 1 -1 2 )
( 1 -2 0 0 1 0 0 0 1 ) E5 E4 E3 E2 E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 0 0 1 1 -1 0 1 0 0 -1 2 0 0 1 1 -1 2 ) (BA|BI)
( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) ( 1 0 0 1 1 -1 0 1 0 0 -1 2 0 0 1 1 -1 2 )
E6 E5 E4 E3 E2 E1 B ( 0 -1 1 1 0 0 2 3 -2 0 1 0 1 2 -1 0 0 1 ) (A|I) = ( 1 0 0 1 1 -1 0 1 0 0 -1 2 0 0 1 1 -1 2 ) ( BA I | BI B )