Question

Find |AB| if A = `[(3,-1),(2,1)]` and B = `[(3,0),(1,-2)]`

Answer 1

AB = `[(3,-1),(2,1)] [(3,0),(1,-2)]`

`= [(9 - 1, 0 + 2),(6 + 1, 0 - 2)] = [(8,2),(7,-2)]`

∴ |AB| = `|(8,2),(7,-2)|`

= - 16 - 14

= - 30

∴ |AB| = - 30