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Mythbusters (mander.xyz)

submitted 4 months ago by fossilesque@mander.xyz to c/science_memes@mander.xyz

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[-] Crowfiend@lemmy.world -2 points 4 months ago

Only if you're rounding. 99.9 is still 1/10 of a digit separated from 100, but it's not equal to 100 for good reason.

[-] chiliedogg@lemmy.world 7 points 4 months ago

But the "...." matters.

[-] Crowfiend@lemmy.world -2 points 4 months ago

It only signifies that the post-decimal nines are repeating infinitely. It still doesn't make 99.99999...=100 unless you intentionally round the value for some nondescript reason, and even then, rounding off isn't changing the value, only the perceived value for mathematical simplicity, not objective accuracy.

[-] chiliedogg@lemmy.world 3 points 4 months ago* (last edited 4 months ago)

".9..." is repeating, but rational. So it's actually "1" . Let's do the math.

.9... / 3 = .3...

.3... = 1/3

1/3 x 3 = 3/3

.9... = 3/3

3/3 = 1

.9... = 1

Still not convinced? We'll use algebra instead of fractions.

0.9... = x

10x = 9.9...

10x - 0.9... = 9

9x = 9

x = 1

[-] Crowfiend@lemmy.world -3 points 4 months ago

So why is it represented as 99.999... Instead of just 100? It's because you're forgetting the fact that fractions and decimals are infinite depending on the magnification. 99.9999... literally goes on forever. That means that no matter how close it gets to 100, it will never be equivalent to 100.

It's like how you can know infinitely nothing and still think you know everything. 👀🫠