On 9/9/2010 3:46 AM, Dan wrote:
> On Wed, 8 Sep 2010, Richard Hennessy wrote:
>
>> Yes, it does mean that. limit(expr1,x,a)-limit(expr2,x,a) is not
>> always equal to limit(expr1-expr2,x,a);
>
> According to my notes on Erd?lyi (1956, _Asymptotic expansions_, Dover
> Publications, New York, pp. 14-15), a linear combination of asymptotic
> expansions of two functions is an asymptotic expansion of the same
> linear combination of the two functions. The same point appears in my
> notes on Hinch (1991, _Perturbation methods_, Cambridge University
> Press, Cambridge, p. 22). A limit has to be asymptotic to the thing
> it's the limit of, no?
no.
> How does all this sit together?
read about limits, instead. I think you will find that
lim(a+b) = lim(a)+lim(b) if lim(a) and lim(b) are finite, or at least
one of them is finite.
RJF