Number 1

Describe the vectors in the column space and nullspace of the following:

In[82]:=

  a1={{0,1,1,1},{0,0,1,0},{0,0,0,0}};
  MatrixForm[a1]

Out[82]=

  0   1   1   1
  
  0   0   1   0
  
  0   0   0   0