= Lima → 0 [(a+2) x a+(a 2-2)]/[a (a+2) x a]+x 2/2,

= Lima → 0 [(a+2) x a+(a 2-2)]/(a * x a) * Lima → 01/(a+2)+x 2/2,

= x 2/2+1/2 * Lima → 0 [(a+2) x a+(a 2-2)]/(a * x a), (type 0/0, the derivative of a molecule).

=x^2/2+ 1/2*lima→0[x^a+(a+2)*x^a*lnx+2a]/(x^a+a*x^a*lnx]，

=x^2/2+ 1/2*( 1+2lnx)，

=(x^2+2lnx+ 1)/2。