Final answer:
The wave described by the function D(x, t) is traveling in the positive x-direction, which is determined by the positive sign of the 't' term in the sine function.
Step-by-step explanation:
To determine the direction of wave travel, we must examine the wave equation D(x, t) = (3.0 cm) sin [2π (x/(2.4 m) + t/(0.20 s) + 1)]. In this equation, x represents the position along the string and t the time variable. The key aspect here is the sign in front of the time term, which tells us about the direction of the wave.
Since the wave equation can be written with 'x' and 't' as (x + vt), where 'v' is the speed of the wave and the '+ vt' term indicates it is moving in the positive x-direction. If the sign had been negative, it would indicate a wave traveling in the negative x-direction. Therefore, the wave described by the given function is traveling in the positive x-direction.
The direction of a wave is determined by the sign of the coefficient in front of the argument of the sine function. In this case, the wave function is D(x, t) = (3.0 cm) times sin [2π (x/(2.4 m) + t/(0.20 s) + 1)]. As the coefficient in front of the argument is positive, the wave is traveling in the positive x-direction.