# Memorising constants



## ben1996123 (Oct 10, 2012)

ok so I'm making this thread because I feel like it and am wondering if anypony else memorises a few digits of numbers n stuff. post stuff you know.

stuff I've memorised:

π: 3.14159265358979323846264338327950288419716939937510582097494459230781640628620899862803482534211706798214808651328230664709384460955058223172535940812848111745028
e: 2.71828182845904523536028747
τ: 6.283185307179586476925286766559005768394338750211
ln 2: 0.6931471805599
ln 3: 1.09
√0.5: 0.707
√0.75: 0.866
√2: 1.414213562373095048801688
√e: 1.64
√3: 1.73205080
√π: 1.77
√5: 2.23
√6: 2.45
√7: 2.64
√8: 2.828
√10: 3.16
√13: 3.60555
√17: 4.12
e^2: 7.38
pi^2: 9.8696
pi^2/6: 1.64
1/e: 0.36
ln pi: 1.14
e^pi: 23.14
pie: 8.539
e^tau: 535.49
φ: 1.618033
sin 1 (degrees): 0.0174
cos 1 (degrees): 0.9998


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## stannic (Oct 10, 2012)

Strange thing, once I've unintentionally memorized 35 digits of Pi...

Pi = 3.14159265358979323846264338327950288+
e = 2.718281828459045+
Ln(Pi) = 1.1447298+
Sqrt(2) = 1.414213562+
Sqrt(3) = 1.73205080807+
Sqrt(5) = 2.23606+
1/7 = 0.(142857)

- stannic


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## Sa967St (Oct 10, 2012)

pi: 1200 digits (I'll reach 1337 by Pi Day next year).
e: 20 digits (I might just do 100 later).
tau: I'd rather just slowly multiply out pi digits by 2 in my head 
ln2/ln3: 3 digits is enough for me.
root2,3,5: currently at 10 digits, I might learn more.
phi: I only know up to 1.6180, but I should learn more.


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## Mikel (Oct 10, 2012)

Here are the numbers I have memorized:

69^0=1
69^1=69
69^2=4761
69^3=328509
69^4=22667121
69^5=1564031349
69^6=1.079181631*10^11
69^7=7.446353253*10^12


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## stannic (Oct 10, 2012)

Mikel said:


> Here the numbers I have memorized:
> 
> 69^0=1
> 69^1=69
> ...



Why 69? The highest factorial that can be calculated?


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## brunovervoort (Oct 10, 2012)

I knew like 190 digits op pi, and 25 of √2.
And thats it.


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## Ickathu (Oct 10, 2012)

I used to know about 175+ digits of pi, but now I just know 3.141592653589793238 off the top of my head. If I wanted to I might be able to remember some more with a little prompting, but I don't care


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## vcuber13 (Oct 10, 2012)

stannic said:


> Why 69? The highest factorial that can be calculated?


its not the highest that can be calculated, its the largest that is less than a googol


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## stannic (Oct 10, 2012)

vcuber13 said:


> its not the highest that can be calculated, its the largest that is less than a googol



Oh well, I meant, using handheld calculator


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## shelley (Oct 11, 2012)

When I was in school, I ended up unintentionally memorizing the value of the ideal gas constant in a couple different units, mass of proton, mass of electron, and elementary charge in coulombs.

You know, stuff that's actually useful for doing your homework.

To be fair, knowing 200 digits of pi was useful for me exactly once: when I won $10 in a Pi Day pi reciting contest.


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## peterbone (Oct 11, 2012)

ben1996123 said:


> ok so I'm making this thread because I feel like it and am wondering if anypony else memorises a few digits of numbers n stuff. post stuff you know.
> 
> stuff I've memorised:
> 
> ...


The Golden ratio is an obvious one absent from your list. You need to memorize it.
You could also memorize the Feigenbaum constants, which relate to chaos theory. They've been calculated to over 1000 decimal places.


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## Rune (Oct 11, 2012)

What´s special with pi^2/6: 1.64?


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## Ickathu (Oct 11, 2012)

peterbone said:


> The Golden ratio is an obvious one absent from your list. You need to memorize it.
> You could also memorize the Feigenbaum constants, which relate to chaos theory. They've been calculated to over 1000 decimal places.





ben1996123 said:


> φ: 1.618033



φ = phi = golden ratio


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## ben1996123 (Oct 11, 2012)

Rune said:


> What´s special with pi^2/6: 1.64?



\( \sum_{n=1}^{\infty}\frac{1}{n^{2}} \)


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## Chrisalead (Oct 12, 2012)

Nobody mentioned the speed of light : 299792458 m/s !
And we all know a bunch of phone numbers (at least people old enough like me who can remember the good old phone with the circle to compose the numbers). Here a phone number is 10 digits.


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## vcuber13 (Oct 12, 2012)

thats km/s


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## Chrisalead (Oct 15, 2012)

vcuber13 said:


> thats km/s



Oups ! My mistake, now it's m/s ^^.


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## PeelingStickers (Oct 17, 2012)

pi: 3


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## stannic (Oct 17, 2012)

e:2
sqrt(13): 3
pi/2: 1.5
sin x: 0 (0 <= x < 1.5)


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