Hi, If you have a Heaviside function such as (u(x-2)-u(x-6), then am I right in thinking that this would be = 1 or 'on' between x=2 and x=6? What happens if you put x in front of the equation? E.g. x(u(x-2)-u(x-6)) Im trying to understand Heaviside but I am getting quite confused by it all at the moment????