# Wave equation in classical mechanics!

1. Mar 30, 2016

### DeNiSkA

My question is about equation of a wave which travells on a string.
I have seen that we write wave function as y=f(x-vt) , but why did we select this function, why not any other like y=f(5x-9vt) .
I also have a question why is there a negative sign why not positive sign, (for me positive one makes sense)

Thank you for helping :)

2. Mar 30, 2016