The rule is f'(x)/f(x) = ln f(x).
So we have x/(x^2 + 2), we need to make the top f'(x) which is 2x.
So 1/2 int 2x / (x^2 + 2) is the same as int x / (x^2 + 2) right?
So 1/2 int 2x / (x^2 + 2) satisfies the rule f'(x)/f(x) = ln f(x).
So 1/2 ln f(x) + C or 1/2 ln (x^2 + 2) + C.