Find the minor and cofactor, respectively, for element 2 in the matrix ∆ = \(\left( {\begin{array}{*{20}{c}} 6&5\\ 2&4 \end{array}} \right) \)

Question

Question

This question was previously asked in

AAI ATC Junior Executive 27 July 2022 Shift 1 Official Paper

Answer 1

Calculation-

∆ = \(\left( {\begin{array}{*{20}{c}} 6&5\\ 2&4 \end{array}} \right)\)

Element '2' is of row 2 and column 1 so it is represented as 'a₂₁'

In 2 × 2 matrix minor is simply the diagonally opposite element.

Minor of element M₂₁ = 5

Cofactor of element A₂₁ = (-1)²⁺¹ M₂₁

Cofactor = -5

∴ minor and cofactor of element 2 are 5 and -5 respectively.