An orbital path of a satellite might be 60k miles, or say 10^4 miles. An error of 10^-15 would translate to 10^-11 miles, or ~10^-7 inches. So all those digits may be gratuitous. For anything beyond Earth orbit, I imagine there are uncertainties that far exceed that precision level.

That said, as a chemical engineer I always used conversion constants to as many digits as my calculator allowed. This makes sure that, if two calculations of the same thing are not numerically identical, then something was different about the calculations. So it was a sort of fingerprint that I could use to review work. The side benefit was that I remembered things like pi and e all to at least 8 digits.

 

Out of curiosity, how precisely can you remember pi off the top of your head? For me, it's 3+7 decimal digits.

 

3+10 decimal digits Been that way a long time.

I am blessed with 10 grandchildren, so far. Two of my granddaughters are into math. One (age 12) even got her math teacher excited about some of the links I sent. There is nothing like being a nerd and proud of it. They have all had fun with this link: http://www.subidiom.com/pi/

John

 

I can recall pi to 10 places.

If you want a good approximation to 6 places, use 355/113.

 

Can only be Pi Day in the States! The rest of the world will miss out, as there aren't 14 months in a year .

It's too bad there isn't an April 31st. If there was, 31/4/15 could be British Pi Day.

No pie for you.

Actually, the British have it better than Americans, because Pi Approximation Day (July 22) can only be represented correctly in British date format (22/7). So while Americans can only eat pies on Pi Day, the British can eat anything that approximates pie on July 22, including cake, cookies, and ice cream.

 

It's too bad there isn't an April 31st. If there was, 31/4/15 could be British Pi Day.

Actually, the British have it better than Americans, because Pi Approximation Day (July 22) can only be represented correctly in British date format (22/7). So while Americans can only eat pies on Pi Day, the British can eat anything that approximates pie on July 22, including cake, cookies, and ice cream.

Blood pudding, too?

 

Blood pudding, too?

Does that refer to:

1. a sausage made with animal food
2. a North Vietnamese blood pudding
3. a Scandinavian dish
4. solidified pig's blood

 

Does that refer to:

1. a sausage made with animal food
2. a North Vietnamese blood pudding
3. a Scandinavian dish
4. solidified pig's blood

Now, I am in over my head. I just had a Brit boss once who talked about it, but he also talked about a lot of things I never understood.

 

Now, I am in over my head. I just had a Brit boss once who talked about it, but he also talked about a lot of things I never understood.

That's funny. I looked it up on Wikipedia because I didn't know what it was, and it listed those four different meanings. I would assume that your boss was referring to #1 because that appears to be the British definition, but I'm not sure.

 

3.141592653590 I count 12 digits after the decimal. That's all my calculator could handle.

2.718281828 Hmmm, only 9 digits in memory for e. I guess that's all my brain could handle.

 

I used to pass through the Manchester airport fairly often and it always worked out that I was there after a long, international, overnight flight, just in time for breakfast. I would break down and get the "big" breakfast that included some godawful black sausage. Each time I would resolve to not get it ever again, but each time I would be so hungry that I could not resist. A colleague told me it was blood sausage. I prefer to not think about it.

Anyway, happy π day.

 

That's funny. I looked it up on Wikipedia because I didn't know what it was, and it listed those four different meanings. I would assume that your boss was referring to #1 because that appears to be the British definition, but I'm not sure.

Now that I think about it, he said, "blood sausage." And it was "Christmas pudding" that he also talked about; he brought that to work once; I wish it had been blood sausage.

 

Out of curiosity, how precisely can you remember pi off the top of your head?

I 'remember' it to 30 decimal places by reciting the following verse about Archimedes :-
"Now I, even I, would celebrate in rhymes inept
The great immortal Syracusan, rivall'd nevermore,
Who, in his wondrous life passed on before,
Left men his guidance how to circles mensurate"

 

Hello,

Digits of Pi

First 100 digits

3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 ...

First 1000 digits
3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 4811174502 8410270193 8521105559 6446229489 5493038196 4428810975 6659334461 2847564823 3786783165 2712019091 4564856692 3460348610 4543266482 1339360726 0249141273 7245870066 0631558817 4881520920 9628292540 9171536436 7892590360 0113305305 4882046652 1384146951 9415116094 3305727036 5759591953 0921861173 8193261179 3105118548 0744623799 6274956735 1885752724 8912279381 8301194912 9833673362 4406566430 8602139494 6395224737 1907021798 6094370277 0539217176 2931767523 8467481846 7669405132 0005681271 4526356082 7785771342 7577896091 7363717872 1468440901 2249534301 4654958537 1050792279 6892589235 4201995611 2129021960 8640344181 5981362977 4771309960 5187072113 4999999837 2978049951 0597317328 1609631859 5024459455 3469083026 4252230825 3344685035 2619311881 7101000313 7838752886 5875332083 8142061717 7669147303 5982534904 2875546873 1159562863 8823537875 9375195778 1857780532 1712268066 1300192787 6611195909 2164201989

http://www.math.com/tables/constants/pi.htm

Bertus

 

@bertus: Am I correct that you didn't remember all those digits off the top of your head?

 

I 'remember' it to 30 decimal places by reciting the following verse about Archimedes :-
"Now I, even I, would celebrate in rhymes inept
The great immortal Syracusan, rivall'd nevermore,
Who, in his wondrous life passed on before,
Left men his guidance how to circles mensurate"

That explains it.

 

Hello,

No, of course not. If you need it, you can always look it up.

Bertus

 

Hello,

No, of course not. If you need it, you can always look it up.

Bertus

Thanks, but 3.1416 is as close as I have ever needed.

 

No need to memorize 3.14 yadda, yadda, yadda...
Pi will soon be replaced with Tau. Tau = 2 Pi.

Most equations that require Pi deal with 2 x radius, so why not incorporated the 2 into the value of the constant Pi?

See below.
http://lightyears.blogs.cnn.com/2012/06/28/tau-day-why-you-should-eat-twice-the-pie/

MIT historically sent admission letters on Pi day, this year they are sending them at Tau-time on Pi day (6:28).

Cheers and stop wasting your time memorizing pi.

 

Unfortunately, 628-318-5307 is on the left coast -- closer to Stanford, actually.

John