Before revision: It is readily shown that one can combine the above node-voltage equations for all nodes, and write them down in the following matrix form or simply The matrix on the left hand side of the equation is singular since it satisfies where is a column matrix .
After revision: It is readily shown that one can combine the above node-voltage equations for all nodes, and write them down in the following matrix form or simply The matrix on the left hand side of the equation is singular since it satisfies where is an column matrix containing only 1s .