For X=(x1,x2,x3)T∈R3, consider the quadratic form:
Q(X)=2x12+2x22+3x32+4x1x2+2x1x3+2x2x3. Let M be the symmetric matrix associated with the quadratic form Q(X) with respect to the standard basis of R3.
Let Y=(y1,y2,y3)T∈R3 be a non-zero vector, and let
an=YT(M+I3)nYYT(M+I3)n+1Y,n=1,2,3,… Then, the value of limn→∞an is equal to (in integer).