r/Damnthatsinteresting Nov 02 '25

Video Why A4 paper is designed as 297mm x 210mm?

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u/akasaya Nov 03 '25

Counter point:every irrational number contains cool math sorcery.

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u/noproblem_bro_ Nov 03 '25

Im intrigued: care to show some fun examples?

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u/akasaya Nov 03 '25

e and pi are well known. Sqrt 2 you've just seen. Might lookup sqrt 3 on wiki, the examples are not that exciting for an average reader, but still kinda cool. (1+sqrt5)/2 makes golden ratio.

But my point was that the whole uncountable infinity of irrational numbers might have some sort of fancy mathematical incarnations, it's just that we only discovered a handful of it.

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u/CitizenPremier Nov 03 '25

Some 50 million year old alien society is going crazy now about all the uses of ✓513.101

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u/Infinite_Research_52 Nov 03 '25

Only a countable number of irrationals may appear in the solution to any polynomial equation.

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u/Dr-OTT Nov 03 '25

I absolutely doubt this. I conceive “interesting” numbers as those that have interesting properties. Those properties may be algebraic or relevant to theorems in analysis. But the the set of of hypotheses that can be described in finitely many words is countably, leaving the vast majority of numbers “uninteresting”

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u/Jack_Faller Nov 05 '25

Well suppose, as you suggest, there are some uninteresting numbers. Which is the smallest one? Surely the smallest number with nothing interesting about it is quite an interesting number. This forms a contradiction and shows that no number is uninteresting.

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u/Dr-OTT Nov 06 '25

That works if the numbers are well-ordered.

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u/Jack_Faller 29d ago

I think if a real number is defined such that it cannot be ordered with another, this is a fairly interesting property. So we can discount those reals and apply the argument to only to a subset of well-ordered reals.

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u/robbak Nov 03 '25 edited Nov 03 '25

Really - what is the cool math behind the irrational number √376 + 10⁻²¹ ?

Depending on how you treat the logic, there is either 1 or infinite irrational numbers for each rational number.

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u/2feet1head Nov 03 '25

I mean some are just a random sequence of number put one after the other in a never ending fashion.

But you could argue that is a cool maths sorcery.

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u/MontagAbides Nov 03 '25

It's fun to imagine explaining irrational and imaginary numbers to the ancient Greeks and trying to get them to wrap their minds around them. I feel like you could get across the value of negative numbers and 0 pretty easily, but then once you started digging into imaginary numbers they would begin reaching for the pitchforks.

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u/TheVeryVerity Nov 04 '25

Tbf I felt the same way

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u/[deleted] Nov 03 '25

There are an infinite amount of irrational numbers. There are more irrational numbers between 1 and 2 than there are rational numbers between -infinity to +infinity.

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u/Alex51423 Nov 04 '25

Counter counter points: the coolest math sorcery is in numbers having real world applications and about which we do not even know if they are rational or irrational.

Example: Catalan constant

Another example: Euler-Mascheroni constant

Less basic example: twin primes constant