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.