# Thread: Pi is out! Tau is in!

1. Originally Posted by Tomatketchup
I don't see why there can only be one. Just mention quickly tau is 2pi and that 2pi is an alternative if anyone feels more comfortable using it.
If you gonna mention pi - why bother adding tau? Doesn't it complicate things for kids?

2. Originally Posted by Tomatketchup
I don't see why there can only be one. Just mention quickly tau is 2pi and that 2pi is an alternative if anyone feels more comfortable using it.
Because there's no reason to do so. All over math, you throw coefficients in front of things. Might as well get used to it.

3. This has been an ongoing debate. Tau is just double Pi. There is no real advantage to it. You can use either or and get equations done the same.

4. Originally Posted by ag666
If you gonna mention pi - why bother adding tau? Doesn't it complicate things for kids?
Not for me, no.

5. Originally Posted by Tomatketchup
Not for me, no.
But we are not talking about you. You know what a pi is and you can just go tau = 2pi.

6. Um, how does tau work when making formula for calculating the surface areas and volumes of 3 dimensional objects?

Its been over a decade since I was last studying maths, but it seems like those formula get needlessly complex if you write them in tau, sure it makes circumferences simpler to write, but after that. . .

Can someone show me what they would be, as for some reason this video just struck me as really dumb. But thats 100% guaranteed to be me being dumb lol.

7. Like he said, people have been arguing for tau for a while now. I just find the argument kind of silly. I was never annoyed by the fact that there are 2Pi radians in a circle. I think he overestimates how confusing of a concept that is.

The only reasonable option for the inclusion of tau would be including it as accessory to Pi. But even that just seems to complicate things. If it really bothers some teachers they should just define tau at the beginning of class.

8. Originally Posted by AeneasBK
Um, how does tau work when making formula for calculating the surface areas and volumes of 3 dimensional objects?
Well... surface area of a sphere would be 2*tau*r^2.

Volume would be (2/3)*tau*r^3.

Like I said above: we put coefficients in front of things all the time. Get used to it. Pi is the more fundamental number.

9. Let's extend the idea...

quarter = pi/2
pacman = 3pi/2

EDIT: fixed the pacman

10. I'm 100% behind the pacman.

11. what does this do for metrics of a cone or cylinder? I mean, don't they use Pi in there as well?

12. nzall: it's simple, just replace pi with (1/2)*tau everywhere.

13. I find all this to be rather nonsensical. From the mathematical perspective, pi is clearly a more 'important' number than 2pi, simply because of the Euler's identity (http://en.wikipedia.org/wiki/Euler%27s_identity)

14. He is wrong. Maybe if this was done at an early stage he would be right but he would actually add complexity since you would have to teach about tau then later teach about the relationship of tau and pi so people could use bodys of work that pre-date the use of tau. Then there would be a mix between people using pi and people using tau during a transitional phase so all published papers would be some mix until we finally reached the point of using tau. Its just a pointless rant he is having really.

15. Originally Posted by Annapolis
Like he said, people have been arguing for tau for a while now. I just find the argument kind of silly. I was never annoyed by the fact that there are 2Pi radians in a circle. I think he overestimates how confusing of a concept that is.
If anything, it's way easier to just do radians with tau. I can never remember what 270 degrees radians is with pi, but with tau it's 3tau/4. Simple.
Originally Posted by ag666
But we are not talking about you. You know what a pi is and you can just go tau = 2pi.
You are talking about me, I'm learning trigonometry this very moment in school, and while radians is hardly anything, well, hard, the concept is still complex in a stupid way. Tau makes everything easier when it comes to that.

I can get behind the idea of still using 2pi in physics because there it doesn't have any real structure behind it as it has when it comes to radians, in formulas it's simply 2pi and there's that. 2pi in radians are just stupid, though.

16. Originally Posted by Frah
... all published papers would be some mix until we finally reached the point of using tau...
I doubt that any serious mathematician would even consider using tau... it simply makes no sense. The only things is 'simplifies' is the circle circumference formula (provided radius is used as argument). There is absolutely nothing to be gained from tau. People who advocate it for use in schools must think that the kids are too dumb to learn elementary stuff. School pupils already have to deal with the rules of grammar which are way more arbitrary ^^

17. Originally Posted by Annapolis
Like he said, people have been arguing for tau for a while now. I just find the argument kind of silly. I was never annoyed by the fact that there are 2Pi radians in a circle. I think he overestimates how confusing of a concept that is.

The only reasonable option for the inclusion of tau would be including it as accessory to Pi. But even that just seems to complicate things. If it really bothers some teachers they should just define tau at the beginning of class.
Frankly a kid who can't get thier head around 2 pi probably isn't worth teaching maths above basic arithmatic to. Its great to be able to work out ratios and quick calculations (400g cheese for \$3.29, 500g for £4, which is better value?) but above that they don't need to know. Some brains suit maths some brains suit art or music, or languages (and some can do all obv. bastards) but trying to force maths into the heads where it doesn't belong is kinda futile imo.

18. Originally Posted by Tomatketchup
If anything, it's way easier to just do radians with tau. I can never remember what 270 degrees radians is with pi, but with tau it's 3tau/4. Simple.
lol.

pi = 180.
pi/2 = 90.
270 = 3 * 90 = 3pi/2.

Now do that with tau, starting at:
tau = 360.
tau/4 = 90
270 = 90 * 3 = 3tau/4

Same complexity.

Originally Posted by Tomatketchup
You are talking about me, I'm learning trigonometry this very moment in school, and while radians is hardly anything, well, hard, the concept is still complex in a stupid way. Tau makes everything easier when it comes to that.
No, you know what a pi is - therefore we are not talking about you.

The radians/degree conversion is simple. angle in radians = angel in degrees * pi/180 = angle in degrees * tau/360

Originally Posted by Tomatketchup
I can get behind the idea of still using 2pi in physics because there it doesn't have any real structure behind it as it has when it comes to radians, in formulas it's simply 2pi and there's that. 2pi in radians are just stupid, though.
it's not stupid. it's how it is. a full circle is 2pi.

19. The original idea might be good but on a trivial complexity like 2*pi instead of tau? There are orther artefacts, where removing them would make teaching simpler: Speaking numbers in German and French (89=neunundachzig=quatre-vingt-dix-neuf, one is switched places and the other 4*20+19). USA and their archaic Imperial measure system, dodecimal would also be more practical than decimal etc...

20. The fundamental flaw in the guy's argument is that we don't create constants like π, e or what ever because they make formulas easy.

We make constants to represent fundamental properties, π is a fundamental property of a circle (C/D) and therefore is correct by definition.

Defining ππ or τ or a homer to equal 2π is just part of your working, however they are not fundamental properties of the circle and are therefore not of any interest in pure maths or physics.

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