Linear Algebra and Its Applications · Problem 1.4.6

Matrices and Gaussian Elimination — Gilbert Strang

Mathematics · matrix-notation-and-multiplication

Problem

Write down the 2 by 2 matrices

A

and

B

that have entries

a_{ij} = i+j

and

b_{ij} = (-1)^{i+j}

. Multiply them to find

AB

and

BA