# Math Help - Dealing with

1. ## Dealing with

Let $W$be a subspace of $Kn$ and

$v$is also contained in $Kn
$

Need to determine if $v$ is contained in $W

$

$v$ =

3
1
2
3

W = rowspace(A)

$A =$

2411
3402
1212

over

According to the notes we will find another matrix B where:

$W = nullspace(B)
$

Then after GJ $A =
$

1004
0100
0013

And then aparantlly

From this information you can get a single bias vector
$=$
1
0
2
1

But i dont see how??

Any help would be great

2. I wouldn't worry about finding this "B". The definition of "row space of A" is the space spanned by the rows of A. In order to prove that < 3 1 2 3> is in that rwo space, you must show that it can be written as a linear combination of rows of A: that is, find a, b, c such that a<2 4 1 1>+ b<3 4 0 2>+ c<1 2 1 2>= <3 1 2 3>. That is the same as showing that it is possible to solve 2a+ 3b+ c= 3, 4a+ 4b+ 2c= 1, a+ c= 2, and a+ 2b+ 2c= 3.