I have A = [0 1 ; 3 2] and B = [1 2]. For A / B, I get [0.4 ; 1.4], which is a least squares solution. Here is my problem: where is this documented? I can't see this case covered in the documentation of the mrdivide function. The documentation does say that a least-squared solution is obtained when A is rectangular, but when A is square, all it says is: " If A is a square n-by-n matrix and B is a matrix with n columns, then x = B/A is a solution to the equation x*A = B, if it exists." Since no solution exists, shouldn't it return an error? Or at least, shouldn't the behaviour be documented?