Hello, I currently have a problem with interpreting how this statement was interpreted: We have a rate of change which is dv/dt, and in the given notes, they transformed the expression dv/dt into dv/dx dx/dt (using the chain rule). Then, the whole expression simply turns into v dv/dx (as dx/dt is the rate of change in distance which is velocity). The thing I don't understand is how you can change dv/dt into dv/dx dx/dt. I've noticed that the differentials actually cancel out, but I need the mathematical explanation for this (someone told me that it was due to the chain rule). Could someone please explain this problem carefully to me? Thank you very much for your patience.