Assuming that displacements in one direction in one co-ordinate system, result only in displacements in the same direction in the primed system,

Then equation 3 gives,

Solve for gives,

gives,

which can be re-arranged as,

(equation 5a)

and from relativity,

(equation 5b)

Note: The divisor term will be cancelled out later on. There is no divide by zero problem in the final formula. A more careful but less easy to follow process would have avoided it.

No distortion at right angles to relative velocity edit

 
 

From equation 1

 
 

   

  (equation 1)