# Nullspace of A transpose x

1. Mar 20, 2014

### negation

What does ATx=0 means?

Does this notation means if A = [3,2;1,2;4,4], then, AT = [3,1,4;2,2,4]

and ATx [x1;x2;x3] = 0?

The nullspace of the transposed of the matrix A?

2. Mar 20, 2014

### Staff: Mentor

This doesn't mean anything to me. I believe it should be written ATx = 0. ATx is the product of A transpose and some vector x.

3. Mar 20, 2014

### negation

What significance is there if a question ask if it is consistent or inconsistent?
ATx = 0

4. Mar 20, 2014

### Staff: Mentor

My guess is they're asking whether the multiplication is defined. If x $\in$ R3, and A is as you have in post 1, then Ax is not defined, but ATx is defined.