To PI or not two PI

[ryujin]

QUOTE (Raveen @ Jun 29 2011, 06:59 AM) Heh, I rather agree with Juckto although intellectually tau makes more sense I'd forever be translating it back and forth in my head. Same reason radians never took over from degrees.

Probably because they were Pi Radians. I bet you'd have taken to Tau radians quite nicely

[ryujin]

QUOTE (juckto @ Jun 29 2011, 06:42 AM) Circles affect my job in two ways:

Cross sectional area of pipes/columns. I already have a 1/4pi factor in there, no matter to me if it's a 1/2tau factor.
Roof pitch. Oh yes please give me architectural plans that show a roof pitch of 0.196tau. Not only will I love you, but the builder will too!

Also, http://www.xtranormal.com/watch/12020199/w...listid=23204551

"Are you smoking chronic?"
Heh funny video.
I"m sure builders and the rest of the world will resist change. But still Tau>>Pi as a constant.

[FreeBeer]

QUOTE (Ryujin @ Jun 29 2011, 02:18 PM) I"m sure builders and the rest of the world will resist change.

That's an understatement. Canada officially switched to metric around 1975. Although every kid who's graduated from high school has only ever been exposed to the metric system (they often don't know what a foot or yard is, other than as a reference due to exposure to American television and football), construction plans, for the most part (particularly residential) are still in Imperial measurements. 36 years and nothing's changed.

[madpeople]

QUOTE (avirst @ Jun 29 2011, 01:17 AM) I think it's dumb, either way with out pi would there be the other?

Yes, there would. You get PI by dividing a circumference by a diameter, you get TAU by dividing a circumference by a radius. You can work out either independently of the other, the factor of 2 comes from the fact a diameter is two radii end to end.

QUOTE (juckto @ Jun 29 2011, 11:42 AM) Circles affect my job in two ways:

Cross sectional area of pipes/columns. I already have a 1/4pi factor in there, no matter to me if it's a 1/2tau factor.
Roof pitch. Oh yes please give me architectural plans that show a roof pitch of 0.196tau. Not only will I love you, but the builder will too!

You see architectural plans with roof pitch of 0.392PI and have no problem with them (and builders are happy with them too)?

[lexaal]

In my opinion the number shall be defined as 2*PI*i where i^2 = -1.
In 90% of all cases I was using PI, I used it in combination with a 2.
In 75% of all cases I was using PI, I used it with i (or what EEs are calling "j").

[Cyre]

QUOTE (Raveen @ Jun 29 2011, 02:59 AM) Heh, I rather agree with Juckto although intellectually tau makes more sense I'd forever be translating it back and forth in my head. Same reason radians never took over from degrees.

Trigonometric functions are in radians, if you could call the input an angle. Also as far as i can tell all the physics, pure and applied mathematics are radian-bound.

On a side note, i don't understand why you're all calling tau more 'intellectually reasonable'. It is an arbitrary constant, just as good as any other. This sounds just like university politics.

[juckto]

QUOTE You see architectural plans with roof pitch of 0.392PI and have no problem with them (and builders are happy with them too)?[/quote]
No, the point I was trying to make was proof against the following argument:
QUOTE Dr Hartl reckons people still use degrees as a measure of angle because pi's involvement in radians makes them too unwieldy.[/quote]
I read that as "if we change to tau, we won't need degrees. Therefore degrees will no longer be used. Therefore angles on building plans will be written in Tau," to which my response "oh that will make me happy" was directed.

And another thing, the building industry uses diameter, not radius, (almost) all the time. If I told someone to get a half-inch steel rod for the reinforcing bar, I don't expect them to come back with a rod an inch thick.

[ryujin]

My main point isn't for construction or anything like that. From a pure math point of view tau makes more sense.