Hello everyone, I am currently studying traveling waves and reflection but I didn't understand a part of my last lesson. If we consider a string with a loose end and the other end attached to a wall we expect the string to have zero displacement at the wall and to have a reflected wave "-f(-x-vt)" (given that the incident wave is f(x-vt) ). My question is probably really silly, but I can't understand why the reflected wave is "-f(-x-vt)" and not "-f(x+vt)" (travelling in the other direction, with inverted amplitude). I hope I chose the right section since this is my first post here! Thanks in advance to anyone who will reply to this (probably) really silly question!