we have the wave equation as follows with non zero phase constant:
y(x,t) = ym * sin(k( x  PHI/k)  wt)
or
y(x,t) = ym * sin(kx  w(t + PHI / w))
I don't understand where did the PHI /k or PHI / w came from ??
I understand how did we derive the wave equation but I don't understand this part.
