maxima and minima do not move along the x-axis with time and hence the name
standing or stationary waves. When the string vibrates, all particles of the string
vibrate at the same frequency. Moreover they do so in SHM about their equilibrium
positions, which is the line along which the string lies when at rest. However, as
shown in Figure 6.1, the amplitude of vibration of the particles varies along the
length of the string. These characteristics suggest that the displacement y can be
represented by