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• e^(i * tau) =ï»¿ 1. much cooler :P

• Yeah, I've actually been convinced that in the grand scheme of things tau makes more sense. ï»¿ However, I would have had to explained what tau was first, since most people are much more familiar with pi. I guess I'm just part of the problem.

• Wouldn'tï»¿ e^i*tau be a little problematic since tau= 2pi? It would be e^i*tau/2 then.

• e^(i*pi) = -1 but e^(i*tau) = 1 so theyï»¿ are both beautiful.

• howï»¿ can it be an identity, if there are no variables?

• As long as the equation is always true, its an identity. It's a less interesting identity since you can't plug lots of numbers into it, but itsï»¿ still a tautology and therefore an identity. But you make a good point.

• binary solo?ï»¿

• Alright, so this comes from e^(ix)=cosx+i*sinx, notice that at pi, sin is 0 so the complex term goes away. When solving a differential equation involving sine or cosine, it is easier to use this identity, then solve for the real or imaginary component. Using this,ï»¿ you can also form an identity for cos(x) or sin(x) in terms of e,i, and a few constants. This in turn becomes a powerful machine for generating trig identities (ever see an identity, and wonder "how did they get that?", that's how

• Ohï»¿ wow! Now I'm even more impressed.

• Happy 306th birthday Euler!ï»¿

• I saw?ï»¿

• I came.ï»¿