If →a,→b,→c be any three non - coplanar vectors, then calculate the value of [→a+→b →b+→c →c+→a] is
If ¯a,¯b,¯c are non collinear, non coplanar vectors and x¯a+¯b,x¯b+¯c,x¯c+¯a are coplanar vectors then the value of x is