What is the rigorous thought process in finding the basis for the kernel of a matrix?

51 Views Asked by At

I wish to find a set of basis for the kernel of the matrix

$A = \begin{bmatrix}0 & -1 & 0 & 2 \\ -1 & 0 & 2 & 0 \\ 0 & 3 & 0& -6 \\ 3 & 0 & -6 & 0 \end{bmatrix}$

I perform row reduction of $A$, in which I obtain, $ \begin{bmatrix}0 & -1 & 0 & 2 \\ -1 & 0 & 2 & 0 \\ 0 & 0 & 0 & 0 \\ 0& 0 & 0 & 0 \end{bmatrix}$

This allows me to find the kernel more easily. I find two vectors $\begin{bmatrix} 0 & 2 & 0 & 1 \end{bmatrix}$ and $\begin{bmatrix} 2 & 0 & 1 & 0 \end{bmatrix}$ in the kernel of $A$.

But I know there are infinite amount of vectors in the kernel. So I am stuck.

Since I cannot compute the kernel, therefore I cannot compute the basis for the kernel.

There must be a better way to reason about this.