AA=(({{-3, 0.9, 1.8, 0, 0.3, 0}, {0.75, -2, 1.25, 0, 0, 0}, {0, 0, 0, 0, 0, 0}, {0, 0, 0, -1, 0.9, 0.1}, {0, 0, 0, 1.6, -8, 6.4}, {0, 0, 0, 2.5, 2.5, -5}}));
initialone =(({{1, 0, 0, 0, 0, 0}})) ;
initialthree =(({{0, 0, 1, 0, 0, 0}})) ;
iden ={(({{1, 0, 0, 0, 0, 0}})),(({{0, 1, 0, 0, 0, 0}})),(({{0, 0, 1, 0, 0, 0}})),(({{0, 0, 0, 1, 0, 0}})),(0({{1, 0, 0, 0, 1, 0}})),(({{0, 0, 0, 0, 0, 1}}))};
P[s_] = MatrixExp[s*AA];
x=((initialone.P[30]).(({{1}, {2}, {3}, {4}, {5}, {6}}))) //MatrixForm
y=((initialone.P[3]).(({{1}, {2}, {3}, {4}, {5}, {6}}))) //MatrixForm
z=Sum[i*j*(initialone.P[3])[[1,i]]*(iden[[i]].P[27])[[1,j]],{i,1,6},{j,1,6}]
ans=z-x[[1]]*y[[1]]