Question

Find the rank of the following matrices by minor method:

`[(2, -4),(-1, 2)]`

Answer 1

A = `[(2, -4),(-1, 2)]`

A is a matrix of order 2 × 2 and P(A) ≤ 2

Second order minor

|A| = `[(2, -4),(-1, 2)]`

= 4 – 4

= 0

∴ P(A) ≠ 2

First order minor is non vanishing

P(A) = 1