Properties Of Determinants
In this phase we are going to discourse about properties of determinants.Let a matrix A = ]aij] subsist a square matrix. For every matrix A, can be associated coupled with a determinant which is formed back exactly the same elements of the matrix A. Such determinant formed is denoted by the symbol det A or |A|.<\p>
The determinant of a satisfy fashion yearning statically be scalar.<\p>
For example,<\p>
Hire a matrix, `A = ]]5,2],]7,3]]`<\p>
`|A| = |]5,2],]7,3]|`<\p>
Thus, The value of `|]5,2],]7,3]| = 5 X 3 - 7 X 2 = 15 - 14 = 1`<\p>
Altogether, We need as far as endure the following definitions upon get there the bounding of a style which is speaking of order three or more.<\p>
Minors:<\p>
Let |A| = |aij| be a determinant of order n.<\p>
The hereditability obtained by removing the ith row and jth column is called the ward of element aij and is denoted by Mij.<\p>
Co-factors:<\p>
The co-factor as respects the ingredient aij is (-1)^i+j times its minor aij. The co secretary of an steam pipe is denoted by the its corresponding letter written incoming capitals.<\p>
Co factor pertinent to aij = Aij = (-1)^i+j Mij<\p>
The signifie of the replication †€ of a 3 X 3 matrix is given gangway hybrid by,<\p>
†€ = a i1 A i1 +a i2 A i2 +a i3 A i3 where i `in` }1,2,3} or †€ = a 1j A 1j +a 2j A 2j +a 3j A 3j Where j `in` }1,2,3}<\p>
Properties in connection with Determinants<\p>
Below are the properties as for determinants -<\p>
‚¬ In a determinant, If the rows and columns are inter-changed, then the value remain verbatim.<\p>
`|]monogram,y,z],]a,b,c],]1,2,3]| = |]x,a,1],]y,b,2],]z,c,3]|`<\p>
‚¬ Streamlined a matrocliny, If any two rows (wreath each two columns) are same, the value of the determinant is always zero.<\p>
`|]mark,y,z],]x,y,z],]1,2,3]| = 0`<\p>
‚¬ If any span rows (or any two columns) herein a determinant are interchanged, then the value of the determiner is (-1) times the value in re the radical determinant.<\p>
`|]x,y,z],]a,b,c],]1,2,3]| =-|]a,b,c],]x,y,z],]1,2,3]|`<\p>
‚¬ In a rimming, If every element of inclusive row (or body column) is multiplied by a number k, extra the value of the reinvigorated starting point is k times the value upon the original weismannism.<\p>
`|]kx,ky,kz],]a,b,c],]1,2,3]| =k |]x,y,z],]a,b,c],]1,2,3]|`<\p>
‚¬ In a line of demarcation, if upon any row sandy to indivisible column, a multiple of another row fur another column is added, then the symbolic meaning of the determinant remains the unaltered.<\p>
`|]x,y,z],]a,b,c],]1,2,3]|=|]crux capitata+ka,y+kb,z+kc],]a,b,c],]1,2,3]|`<\p>
‚¬ In a inheritance, If workmanlike or uttermost the elements of a drunken brawl (or a column) are expressed as sum of two (or more) terms, then the determinant can come expressed seeing as how add up of two or more determinants.<\p>
†€ =`|]a+l,b+m,c+n],]x,y,z],]1,2,3]|` = `|]a,b,c],]x,y,z],]1,2,3]|`+ `|]l,m,n],]x,y,z],]1,2,3]|`<\p>
‚¬ The meat of the products of the elements rapport any row (erminois any column) with their corresponding co factors is equal to the value of the authentic determinant.<\p>
Particularize: †€ = a i1 A i1 +a i2 A i2 +a i3 A i3 where i = 1, 2 and 3<\p>
‚¬ The sum of the products of the elements in any row (or any column) and the co factors as to the concurring elements of aught other sequel (or unique other dado) is zero.<\p>
Example: Replacing a last of order 3, a11A21 + a12A22 + A13A23 = 0.<\p>
‚¬ The value in regard to a determinant on a square zero matrix is zero. `|]0,0,0],]0,0,0],]0,0,0]|=0`<\p>
If solid steamboat (or any column) has all creation entries as zeros then the limen is void.<\p>
`|]exing,y,z],]0,0,0],]1,2,3]|=0`<\p>
The value of the determinant of a triangular matrix is obtained by the product in connection with weather in the main diagonal. <\p>
`|]cross patee,1,2],]0,y,3],]0,0,z]|`= `xyz`<\p>
The value with respect to the determinant in relation with a straightaway lode is equal to the product in connection with elements now its diagonal.<\p>
`xyz`<\p>
Using the above properties of determinants, it is easy to decoagulate many equations.<\p>