definitions of constants such as pi and e

[osmium]

Which bit of lore?

I can't believe this is a serious question, but anyway. One definition of
lore is "Knowledge acquired through education or experience."

The average person does not know that pi = 4*atan(1) so that makes it lore.

Some more lore:

o How to swap a and b without using a temporary variable
o The problem is on line 42
o The Death Station 9000 will vomit
o Big endian is different than little endian

 

[Matt]

:




I can't believe this is a serious question, but anyway. One definition of
lore is "Knowledge acquired through education or experience."

The average person does not know that pi = 4*atan(1) so that makes it lore.

The "It" in Mr. Plauger's answer to my question referred to the literal
value, not (as you seemed to believe) to the atan expression. That is a
partial explanation of your disbelief.

 

[Matt]

:




But the more likely reason it is used is someone simply showing off his
erudition. Anyone who knows this bit of lore also has a perfectly good
value for pi available to him somewhere in his archives or by making a few
key strokes.

Ah yes, I remember those days well, the group gathered 'round the
campfire listening to the elders ... one old sage telling us how he got
out of a tight spot once by integrating the gamma function ... and the
tall thin old trig teacher admonishing us to always remember that 4
times the arctan of 1 is pi ... But it was only years after my
initiation that I was informed by another graybeard that that holds for
_all_ values of 1 ...

 

[Walter Bright]

But the more likely reason it is used is someone simply showing off his
erudition. Anyone who knows this bit of lore also has a perfectly good
value for pi available to him somewhere in his archives or by making a few
key strokes.

My roommate in college once wrote a program to generate Pi to 10,000
places. To test it, he'd run it to generate 2 or 3 hundred places. I
asked him how he knew it was producing the right values. He said he knew
just by looking at it, because in high school he'd memorized Pi to 800
places.

 

[persenaama]

The average person does not know that pi = 4*atan(1) so that makes it lore.

The average person never went to high school but is programming in C++
sounds super feasible. I always thought that trigonometry is
mathematics and very commonly known. Doh!

 

[Tomás]

persenaama posted:

The average person never went to high school but is programming in C++
sounds super feasible. I always thought that trigonometry is
mathematics and very commonly known. Doh!

But it's a certain kind of person who has a true interest in trigonometry.
For people like myself, I learn it in school/college, and three months
later it's forgotten.


-Tomás

 

[osmium]

The average person never went to high school but is programming in C++
sounds super feasible. I always thought that trigonometry is
mathematics and very commonly known. Doh!

The gal who taught me trig wouldn't understand what that meant. But she
knew what 4 tan^-1(1) and what 4 arc tan(1) were. You probably went to a
better school than I did, we couldn't all be that lucky. <Sigh>

 

[osmium]

The gal who taught me trig wouldn't understand what that meant. But she
knew what 4 tan^-1(1) and what 4 arc tan(1) were. You probably went to a
better school than I did, we couldn't all be that lucky. <Sigh>

On further thought, I have no reason to believe that my high school teacher
had any notion of what a radian was (or is). You can teach trigonometry
perfectly well by measuring angles in degrees. She would probably have
looked in a table in a book and seen that a 45 degree angle corresponds to a
tangent of 1. So 4 x arc tan(1) = 4 x 45 and pi should, of course, be set
to 180.