Question

Find the adjoint of the following:

`[(2, 3, 1),(3, 4, 1),(3, 7, 2)]`

Answer 1

A = `[(2, 3, 1),(3, 4, 1),(3, 7, 2)]`

adj A = `[(+|(4, 1),(7, 2)|, -|(3, 1),(3, 2)| + |(3, 4),(3, 7)|),(-|(3, 1),(7, 2)|, +|(2, 1),(3, 2)| - |(2, 3),(3, 7)|),(+|(3, 1),(4, 1)|, -|(2, 1),(3, 1)| + |(2, 3),(3, 4)|)]^"T"`

= `[(+(8 - 7), -(6 - 3), +(21 - 12)),(-(6 - 7), + (4 - 3), -(14 - 9)),(+(3 - 4), -(2 - 3), +(8 - 9))]^"T"`

= `[(1, -3, 9),(1, 1, -5),(-1, 1, -1)]^"T"`

adj A = `[(1, 1, -1),(-3, 1, 1),(9, -5, -1)]`