Having trouble understanding why the r-th mean tends to the geometric mean as r tends to zero I am having trouble understanding the proof of Theorem 3 in "Inequalities" by Hardy, Littlewood and Pólya. This theorem states that the r-th mean approaches the geometric mean as r approaches zero. I have seen the following post which makes things a little clearer (albeit using o(r) instead of O(r^2)): Why is the 0th power mean defined to be the geometric mean? However, I still cannot determine why: (a): a^r=1+r.log(a)+o(r) as r tends to zero and (b): lim_(r->0)(1+rx+o(r))^(1/r)=e^x. I have a pretty solid grasp of limits, as well as the log and exp functions, but I have never really been taught anything substantial on big/little-O notation, in particular as the variable approaches zero. Could some
clovnerie0q
Answered question
2022-10-03
Having trouble understanding why the -th mean tends to the geometric mean as tends to zero
I am having trouble understanding the proof of Theorem 3 in "Inequalities" by Hardy, Littlewood and Pólya. This theorem states that the -th mean approaches the geometric mean as approaches zero.
I have seen the following post which makes things a little clearer (albeit using instead of :
Why is the 0th power mean defined to be the geometric mean?
However, I still cannot determine why:
(a): as tends to zero,
and
(b):
I have a pretty solid grasp of limits, as well as the log and exp functions, but I have never really been taught anything substantial on big/little-O notation, in particular as the variable approaches zero. Could somebody point me towards a suitable proof of (a) and (b) above please.