left divide discrepancy

I'm sure there is a simple explanation for this...

Lets say I have matrix equation, Ax=B, with A as a 3x3 matrix and x and B as column vectors.

So while in MATLAB, if I input B/A in the command window it says that there is an error using mldivide (left division). HOWEVER, according to the MATLAB help page here, http://www.mathworks.com/help/techdoc/ref/mldivide.html , mldivide, or left matrix division, has the syntax of A\B.

So I guess my question is, what is left division, is it B/A, or A\B? The error script in MATLAB suggests the former, whereas the online help file suggests the later.

Thanks,

Darren

[Walter Roberson]

Which version are you using? For "/" I get messages about mrdivide, not mldivide.

Answer 1

[Wayne King]

mldivide(A,B) is A\B If B is 3x1 and A is 3x3, then B/A should give you a dimension error, but A\B should give you basically inv(A)*B.