hello everyone. I'm studying for the exam now and I understand if a wave is moving in the negative x direction to the left, the value infront of the x should be positve. But you see where he took off -1/2, because i wrote down m/s? Do you know why? its v^2, i thought that just means take the value of v, square it. should it have been m^2/s^2? http://img112.imageshack.us/img112/5643/lastscan4bc.jpg [Broken] Thanks!