Let A be a square matrix all of whose entries are integers.

Question

Let $A$ be a square matrix all of whose entries are integers.

Then which one of the following is true?

Accepted Answer

As all entries of square matrix $A$ are integers, therefore all co-factors should also be integers.

If det $$A =  \pm 1\,\,$$  then $${A^{ - 1}}\,\,$$ exists. Also all entries of ${A^{ - 1}}$ are integers.

Solutions · 1