how we can get matrix of p[2],p[0] and p[1] when p[2]=1,p[0]=1 and  p[1]=-x and x[0]=-1,x[1]=-2/3 ,x[3]=0 when the general matrices of p are given below.....and answer should be p[2]=p[0]= identity matrix and p[1]= only diagonal values are 1,2/3,1/3,0..

How we can generate given matrix A with help of loop?