How many digits of e do you know?

[cmacis]

Generally we're put to shame on this. Few go past 2.71. Heck, most people who know what it is would have to think before getting the 2.

I can't go past 2.71 at the moment, but I could probably calculate more in my head using the sum.

[EvanED]

2.
71828 18284
59045

So 15, but only because it follows a pattern. 18 28 18 28... piece of cake.

[gmalivuk]

For this one I only ever remember 2.718281828

Why would you remember it only to 2.71? At least you could round it up to be closer to the actual value.

[cmacis]

I don't ever round it up because:
a) I don't know the next digit to know if it needs rounding
b) I never need the decimal for exp(x) except if it comes out as a integer (through a log say).

[SpitValve]

For this one I only ever remember 2.718281828

Why would you remember it only to 2.71? At least you could round it up to be closer to the actual value.

e is such a nice number to memorise. 2.718281828 is as far as I go too. It's got a pretty pattern to it that rolls off the tongue. Just say it! Two point seven one eight two eight one eight two eight. (3.14 is what I can do for Pi...)

[skeptical scientist]

2.718281828
Why would anyone memorize anything else?

[warriorness]

I think 2.718281828 is gonna be the vast majority on this one. (I'm part of it)

[The LuigiManiac]

As ashamed as I am to say this, none. Mainly because I haven't been taught it yet in school.

[Solt]

My multivariable calc GSI said it was discovered in 1828, so the value is 2.7 1828 1828

It works for me, true or not.

[skeptical scientist]

It's definitely not true. According to Wikipedia, which is generally correct on math-related articles,

The first references to the constant were published in 1618 in the table of an appendix of a work on logarithms by John Napier. However, this did not contain the constant itself, but simply a list of natural logarithms calculated from the constant. It is assumed that the table was written by William Oughtred. The first indication of e as a constant was discovered by Jacob Bernoulli, trying to find the value of the following expression:


The first known use of the constant, represented by the letter b, was in correspondence from Gottfried Leibniz to Christiaan Huygens in 1690 and 1691. Leonhard Euler started to use the letter e for the constant in 1727, and the first use of e in a publication was Euler's Mechanica (1736). While in the subsequent years some researchers used the letter c, e was more common and eventually became the standard.

[EstLladon]

2.1828182845904523

Somehow I was taught that 1828 is the year in which Leo Tolstoy was born. Having cultural background is good.

[PaulT]

2.1828182845904523

Somehow I was taught that 1828 is the year in which Leo Tolstoy was born. Having cultural background is good.

Unless it causes you to miss out a 7?

I just remember that it's 2.7 then some 1828s. Never remember how many though, so I just pretend it's a recurring decimal (and therefre rational and therfore all of maths collapses on itself, but I choose to ignore this).

[gmalivuk]

I guess from now on it shouldn't be too hard to remember the 45904 that comes after 18281828, as it is one of the ZIP codes in Grand Rapids, MI, near where I grew up.

So yeah, now I vow that the amount of e I will remember shall be no less than

2.71828182845904

[aguacate]

When I worked at a call center years ago I saved my head from exploding by memorizing some e digits:

2.71828182845904523536

Although to be honest my fingers know it better than my head do. To recall it sometimes I have to imagine myself typing on the number pad.

[cmacis]

I had that problem with a pin number. I used the same for online banking and for the atm. The keypads on computer and atm were the opposite ways around, so I kept getting one of them wrong.

[gmalivuk]

When I worked at a call center years ago I saved my head from exploding by memorizing some e digits:

2.71828182845904523536

Although to be honest my fingers know it better than my head do. To recall it sometimes I have to imagine myself typing on the number pad.

I was like that when I was memorizing Pi by putting bits of it into my university password.

[adlaiff6]

2.7
1828
1828
45
90
45

Two point seven, two copies of "1828", and then every mathematician's favorite three angles (not really, but they are common angles)

[cmacis]

You're using degrees for angles?

/me faints.

Heh, I still think in degrees often, but write radians.

[skeptical scientist]

I use radians for angles when I'm doing math, and degrees for angles when I'm doing other things. Unless I want an expression for a large random angle, which is "a radian".

[adlaiff6]

You're using degrees for angles?

/me faints.

Heh, I still think in degrees often, but write radians.

Look. The memory device doesn't work unless you use degrees. Get over it.

If you're serious about the question, of course I use radians for serious maths.

[ijmaxwell]

I know all the digits of e:

1/0! + 1/1! + 1/2! + 1/3! + .....

If you'd prefer the decimal expansion, tell me how many digits you want and give me a few minutes.

[bbctol]

I know all the digits of e:

1/0! + 1/1! + 1/2! + 1/3! + .....

If you'd prefer the decimal expansion, tell me how many digits you want and give me a few minutes.

What's 1/0! ? That doesn't look possible...

[crazyjimbo]

What's 1/0! ? That doesn't look possible...

0! = 1

[Torn Apart By Dingos]

I know all the digits of e:

1/0! + 1/1! + 1/2! + 1/3! + .....

If you'd prefer the decimal expansion, tell me how many digits you want and give me a few minutes.

I want 10^100 digits. Get on it.

[LE4dGOLEM]

proper hardcore nerd know at least 3 trancendentals to 25+

[Twasbrillig]

2.718281828.

But I know 125 digits of pi!

Working on phi as well.

[Mike Graham]

But I know 125 digits of pi!

I can name twice that right now! 250 digits! They're all 4, and I have no idea where they occur.

[Solt]

You're using degrees for angles?

/me faints.

Heh, I still think in degrees often, but write radians.

cmacis: "Soldier, raise firing angle to 2-pi over 9 radians!"
soldier: "whaaa"
/cmacis gets hit by artillery shell

[Andrew]

I know all of them.

But I can't remember what order they go in.

[cmacis]

Heh, transcendentals you say?

Sigma 10^-n! (n=1...infinity) is easy enough to remember. 1 is the decimal place is a factorial, 1 otherwise. First number to be proven to be transcendental I think.

[LE4dGOLEM]

Sigma 10^-n! (n=1...infinity)

Don't factorials go down, rather than up though? (5*4*3*2*1 rather than n1*2*3*4*5 ?)

[Andrew]

Sigma 10^-n! (n=1...infinity)

Don't factorials go down, rather than up though? (5*4*3*2*1 rather than n1*2*3*4*5 ?)

What difference does it make?

cmacis is (I assume) referring to the number you get if you take every natural number, feed them into the equation 10^(0-(n!)), and add up all the results. It's a naught, then a point, then an infinite row of ones and zeroes.

And it works whatever order you multiply in.

[FiddleMath]

two-point-... uh ...

Honest, I use the thing all the time, symbolically, but all I've ever needed to know formally is that it falls between 2 and 3. Of course, I never compute that actual values of things, I just show how they can be calculated. This is considered generally sufficient in CS. But now I'll know it better, honest.

[gmalivuk]

Sigma 10^-n! (n=1...infinity)

Don't factorials go down, rather than up though? (5*4*3*2*1 rather than n1*2*3*4*5 ?)

cmacis's notation meant the sum, as n goes from 1 to infinity, of 10^-n!. So the 1s in the decimal expansion only occur at the first place, 2nd place, 6th, 24th, 120th, etc places.

[Amnesiasoft]

I only know 2.718...

maybe I'll remember the double 1828...

or maybe not...

[Eschatokyrios]

I only knew 2.7 before I opened this thread. But usually when I use e, I use the e^x button on my calculator, so I don't need to memorize it.

[Jach]

2.718281828

I seem to recall my Math teacher saying something about the 7th president being in office the first time in 1828 and being elected twice...

TAW says that he was kind of right, but not really... Or that I'm just not focusing on the words right now. Or that my memory is just messed up.

[SpitValve]

I tried to calculate e in my head from the Maclauren series during the graduation lectures today. I think I only got as far as 2 and something over 120. I'm not very good at mental arithmetic...

[Ended]

0.20 787 957

wait, no...

Bonus question: which number is that?

[EndangeredMassa]

i^i = 0.20787957