The Eq.(2.4) can be rewritten as

(2.6) 
which can be further simplified as

(2.7) 
where stands for the distance traveled by the acoustic wave.
Therefore, it follows that

(2.8) 
stands for the travel time along .
For a wave propagating between two points and the total travel time corresponds then to

(2.9) 
Subsections
Orlando Camargo Rodríguez
20120621