A = [ a b . . . b ]

[ b b . . . b ]

[ b b . . . a ]

What is the determinant of A?

What conditions would allow det A not equal to 0?

My answers:

det A = 2a (ba - b^2) or 0, since the middle terms would all be eliminated.

det A not equal to 0 when a not equal to 0, with the number of row + number of columns = even.