00:01
So we're given a matrix, a and b, and we want to determine whether the determinant of ab is equal to the determinant of a times the determinant of b.
00:11
Well, ab is negative 1, negative 1, negative 1, 4, negative 2, 7, 4, 1, and negative 5.
00:24
So the determinant of a, which is, let's see here, i want the determinant of a.
00:44
So matrix math, the determinant of a is 9, the determinant of b is negative 7, and the determinant of ab is equal to negative 63.
01:31
So the determinant of ab is equal to the determinant of a times the determinant of b, because negative 63 is equal to 9 times negative 7.
01:48
And then the next one that we want to see is the determinant of a minus b.
01:55
Is that equal to the determinant of a minus the determinant of b? well, a minus b is equal to 0, 0, 1, negative 2, 4, negative 1, 0, negative 1, 2.
02:20
And that means that the determinant of a minus b is equal to 2, and the determinant of a minus the determinant of b is going to be 9 minus negative 7.
02:50
So this is going to be 16.
03:01
And that means that the determinant of a minus b is not equal to the determinant of a minus the determinant of b...