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Topic: Is there a compact form for n-tuple relativistic additions of
velocities?

Replies: 7   Last Post: Jun 4, 2010 6:08 PM

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 stargene@sbcglobal.net Posts: 21 Registered: 11/11/05
Re: Is there a compact form for n-tuple relativistic additions of
velocities?

Posted: Jun 1, 2010 1:30 PM

>
> iirc, the addition formula for the inverse hyperbolic tangent is the
> same as the addition formula for velocities in SR.
> i.e., atanh(x)+atanh(y) = atanh((x+y)/(1+xy)).
> Take tanh of both sides and have fun.

Indeed, I looked it up and you are right. However, as I am
often preternaturally dense, I don't understand how knowing
that makes my task of adding, say, n = 10^6 identical little
velocities, where each one is v = Co / 10^6, (identically one
millionth the velocity of light) any easier without steam
shooting out of my ears.

Eg: How would taking the tanh of both sides of your relation
help me, and how does that take into account the totality of
all my n= 10^6 additions? And when n = 10^9 or more? :-(

Gene

Date Subject Author
5/29/10 stargene@sbcglobal.net
5/31/10 Martin Cohen
6/1/10 stargene@sbcglobal.net
6/2/10 Martin Cohen
6/3/10 Martin Cohen
6/4/10 stargene@sbcglobal.net
6/4/10 Ilya Zakharevich
6/4/10 Martin Cohen