Relativity
The Special and General Theory

also satisfy (2). Obviously this will be the case when the relation

(x' - ct') = λ(x - ct)

(3)

is fulfilled in general, where λ indicates a constant; for, according to (3), the disappearance of (x - ct) involves the disappearance of (x' - ct').

If we apply quite similar considerations to light rays which are being transmitted along the negative x-axis, we obtain the condition

(x' + ct') = µ(x + ct)

(4)

By adding (or subtracting) equations (3) and (4), and introducing for convenience the constants a and b in place of the constants λ and µ, where

a =	λ + µ
	2

and

b =	λ - µ	,
	2

we obtain the equations

x' = ax - bct ct' = act - bx

(5)

We should thus have the solution of our problem, if the constants a and b were known. These result from the following discussion.