Re: Collatz conjecture question

Am 24.03.2025 um 16:27 schrieb Python:

Le 24/03/2025 à 15:47, Richard Hachel a écrit :

 (-5)² = 25
>
 Then -5 = 5

Huh?!
Did this idiot even went to school?
Hint at RH: The function f: IR -> IR defined with f(x) = x^2 (for all x e IR) does not have an inverse. Hence from a² (with any a e IR) you can't "derive" /a/ by applying a "sqrt" inverse function (since there is no such function).
On the other hand there's the function sqrt: {x e IR: x >= 0} --> {x e IR: x >= 0} defined in a way such that sqrt(a^2) = a for all a e {x e IR: x >= 0}.
Hence we may get sqrt(25) = 5, but certainly NOT sqrt((-5)²) = -5. <facepalm>