I have a matrix M which is 3x4.  I need add a fourth row to it.  I've been trying

E:=Matrix([ [M], [0,0,0,1] ])

and

E:=Matrix([ [Row(M,1)], [Row(M,2)], [Row(M,3)], [0,0,0,1] ])

But neither of them worked.  How would I do this?

Thanks,
Dave

I would like to do something like a derivative with respect to a vector or really anything involving a vector (not of a known length or known values) going in and a vector coming out:

diff( Transpose(x) * A * x, x)

Is this possible?

It's just that it is very different if you do x*(x+1) if x is a vector or if x is a scalar.  Does this make sense?
 

Any tips would be great!

Thanks,

Dave