print"A*B is a null matrix does not necessarily imply A=0 or B=0 or B*A=0"
var('A,B')  #initializing two matrices
A=matrix([[1,1],[2,2]])
B=matrix([[-1,1],[1,-1]])
print A
print B
print A*B   # multipling A and B in this order
print B*A   # multipling B and A in this order

Kreyszig-6.2-5 (last edited 2010-12-15 12:45:21 by kirankumar)