martillo
Registered Senior Member
My reasononing is valid for the general case of travelling waves too! I didn't want to restrict to stationary waves and if I did it was just a mistake in notation in the hurry to answer fast.Both Cpt and I have pointed out that your 'general superposition' is wrong. You assume X = X(t). This is known as a stationary wave because the wave doesn't move in space, it just varies in time. THIS IS WRONG.
Good bye.