Dirk Van de moortel wrote:

[snip crap]

>
> Proof:
> The linear transformation (x,t) --> (x',t') is given by
>     x' = P x + Q t
>     t' = R x + S t
> with unknown P, Q, R, S.
>
>


[snip incredible incompetence)

[unsnipped simple derivation]

The wordline of a light signal 
    x' = c t' 
is the transformation of 
    P x + Q t = c (R x + S t) 
which is equivalent with 
    (P - c R) x = (c S - Q) t 
or 
    x = t (c S - Q) / (P - c R) 


If this is to be equivalent with expression of the 
worldline of that light signal in the unprimed coordinates 
    x = c t , 
then the coefficients of t must match, hence 
    c = (c S - Q) / (P - c R) 
so 
    (c S - Q) = c (P - c R) 

Now 
    x' - c t' = P x + Q t - c (R x + S t) 
              = (P - c R) x - (c S - Q) t 
              = (P - c R) x - c (P - c R) t 
              = (P - c R) (x - c t) 

So we have found a lambda such that 
    x' - c t' = lambda (x - c t), 
namely 
    lambda = P - c R. 

Now *that* is what this is about. Big deal. 
[ See also http://groups.google.com/group/sci.physics/msg/6b5525c9583c9766 ] 

Quote from:
   http://groups.google.com/group/sci.physics/msg/6b5525c9583c9766

Demanding that there is a number U such that
        x'-ct' = U*(x-ct)
and that there is a number V such that
        x'+ct' = V*(x+ct)
is a nifty way to do that, since we can now immediately
write
        x' = [U+V]/2 * x - [U-V]/2 * ct
        ct' = -[U-V]/2 * x + [U+V]/2 * ct

unquote

hahahahahahahaha..... So idiot, you have now introduce the concept of
"nifty" physics. I wonder if you understand linear transformations.

You are the Dirt of usenet.


Mike