Can someone please help me solve the following?
$$f=exp\{\frac{P(x)}{Q(x)}\} = exp\{\frac{a+x+O(x^2)}{b+x+O(x^2)}\} = exp\{\frac{a+x}{b+x}+O(x^2)\}=exp\{\frac{a+x}{b+x}\}+O(?)$$
For the nominator $O(x^2) $ as $n\rightarrow0$
For the denominator $O(x^2) $ as $n\rightarrow \infty$
Also is there any good text concerning functions of the big O?