I have to prove the finite speed propagation property for the solutions of the wave equation of the real line using the equation i've attached. But I wasnt sure how to prove it and what does it mean by real line?

- Sep 17th 2008, 08:45 AMpandafinite speed propagation for the solutions of the wave equation
I have to prove the finite speed propagation property for the solutions of the wave equation of the real line using the equation i've attached. But I wasnt sure how to prove it and what does it mean by real line?