Comment on I just cited myself.
ytg@sopuli.xyz 3 months agoSimilarly, 1/3 = 0.3333…
So 3 times 1/3 = 0.9999… but also 3/3 = 1
Another nice one:
Let x = 0.9999… (multiply both sides by 10)
10x = 9.99999… (substitute 0.9999… = x)
10x = 9 + x (subtract x from both sides)
9x = 9 (divide both sides by 9)
x = 1
zarkanian@sh.itjust.works 3 months ago
My favorite thing about this argument is that not only are you right, but you can prove it with math.
ColeSloth@discuss.tchncs.de 3 months ago
Except it doesn’t. The math is wrong. Do the exact same formula, but use .5555… instead of .9999…
Guess it turns out .5555… is also 1.
WldFyre@lemm.ee 3 months ago
Lol you can’t do math apparently, take a logic course sometime
Let x=0.555…
10x=5.555…
10x=5+x
9x=5
x=5/9=0.555…
Reddfugee42@lemmy.world 3 months ago
Oh honey
pyre@lemmy.world 3 months ago
you have to do this now
SmartmanApps@programming.dev 3 months ago
Not a proof, just wrong. In the “(substitute 0.9999… = x)” step, it was only done to one side, not both (the left side would’ve become 9.99999), therefore wrong.
ytg@sopuli.xyz 2 months ago
The substitution property of equality is a part of its definition; you can substitute anywhere.
SmartmanApps@programming.dev 2 months ago
And if you are rearranging algebra you have to do the exact same thing on both sides, always
zarkanian@sh.itjust.works 3 months ago
They multiplied both sides by 10.
0.9999… times 10 is 9.9999…
X times 10 is 10x.
SmartmanApps@programming.dev 3 months ago
10x is 9.9999999…
As I said, they didn’t substitute on both sides, only one, thus breaking the rules around rearranging algebra. Anything you do to one side you have to do to the other.