XII Maths Chapter 4. Determinant | Page 7

86 = 9 x 9 + 5
Area of triangle
Numerical : Find area of triangle with vertices ( 1 , 0 ), ( 6 , 0 ), ( 4 , 3 ) Solution :
Area = ½ ( 1 ( 0x1 – 3 x 1 ) + 0 + 1 ( 6 x 3 - 4 x 0 )) Or Area = 15 / 2
Minors
Minor of an element aij of a determinant is the determinant obtained by deleting its i th row and j th column in which element aij lies . Minor of an element
aij is denoted by Mij .
Minor of an element of a determinant of order n ( n ≥ 2 ) is a determinant of order n – 1 .