00:01
So we have a question here about this matlab output.
00:03
In particular, you've asked, how do we get the result dividing a square matrix by a column? so if you look at what's actually happening here, we have b quote unquote divided by a.
00:17
So we're not dividing a matrix by a column.
00:21
That's not what's happening.
00:22
We're dividing a column b by a matrix.
00:29
And in particular, division doesn't really make sense with matrices.
00:32
Right? you can't.
00:34
As much as multiplication is defined, matrix division isn't defined.
00:37
But what we do have is inverses.
00:40
So we can do m inverse times b or b times m inverse.
00:47
Of course, these are different things because matrix multiplication doesn't always commute.
00:54
And in particular, looking at the matlab here, this is in a backslash instead of an ordinary slash.
01:01
Like ordinary, to divide two numbers, we would have like x forward slash y.
01:06
But here we have b backslash a, which means, because it's a division, we want to look at a inverse.
01:18
So we're multiplying in some sense b and a inverse...