As per the answer at https://math.stackexchange.com/a/573040/23890, the infinite power tower $x^{x^{x^{x^{x^{x^{x^{.{^{.^{.}}}}}}}}}}$ converges if and only if $ x \in [e^{-e}, e^\frac{1}{e} ] $.
Is $ e^{-e} = 0.065988... $ really the lower bound for $ x $ for this power tower to converge?
I wrote a Python program to check how this power tower behaves for $ x < e^{-e} $, for example, $ x = 0.01 $. It seems for $ x = 0.01 $, the power tower converges to $ 0.941... $.
from math import *
def power_tower_iterations(x, iterations):
result = 1
for i in range(iterations):
result = x ** result
return result
def power_tower(x):
for iterations in [10, 100, 1000, 10000, 100000, 1000000]:
print(power_tower_iterations(x, iterations))
power_tower(0.01)
Output:
0.9415490240371601
0.9414883685756696
0.9414883685756696
0.9414883685756696
0.9414883685756696
0.9414883685756696
So does the power tower converge for $ x < e^{-e} $ or does it not? If it does not, what error have I made above that led me to the false conclusion that the power tower converged to $0.941...$ for $x = 0.01$?
Hint :Nice answer is given here by @Simply ,For $0<x<e^{-e}$, it diverges. Note that for such small values of $x$, we get $t>x^{x^t}$ for when $t>y$ and $t<x^{x^t}$ when $t<y$, where $y=x^y$. In other words, adding more powers of $x$ ends up pushing it farther and farther away from $y$ instead of closer. Particularly, it approaches $0$ and $1$, for even and odd powers of $x$. In the same time limit of odd iteration is not the same with limit of even iteration for $0<x<e^{-e}$ as you showed in your code as @Rob Bland claimed above in comment