Hi everyone. I have trouble finding the velocity of a travelling wave give some information about it's displacement. I am given D (x,t)= 1 cm if |x - 4t| <\= 1 &&&D (x,t) = 0 cm if |x - 4t| > 1. I don't know how to interpret these mathematical statements. I've been trying for 3 hours now :(. I have the feeling that it's simple but I simply don't get it. 1) Do they mean that the wave number k=1 and the angular frequency omega=4? ( Inferred from the formula D (x,t)= A cos ( kx +/- wt + phase constant). Does it also mean that the phase constant =0 rad? 2) Am I able to draw a snapshot or hiatory graph from these statements only? If so, can someone give me a hint as of how to proceed? 3) I am asked to find the velocity of the wave. Hint as of how to do that please? Thanks in advance for any help!