Question

If A = `[(2, 1, -1),(0, 1, -2)]`, Find A^t . A where A^t is the transpose of matrix A.

Answer 1

A = `[(2, 1, -1),(0, 1, -2)]`

A^t = `[(2, 0),(1, 1), (-1, -2)]`

A^t . A = `[(2, 0), (1, 1),(-1, -2)][(2, 1, -1),(0, 1, -2)]`

= `[(4 + 0, 2 + 0, -2 - 0),(2 + 0, 1 + 1, -1 - 2),(-2 - 0, -1 - 2, 1 + 4)]`

= `[(4, 2, -2), (2, 2, -3), (-2, -3, 5)]`