Let's say you have a loss of 3% of the current energy on a device for every time is gets turned on. It starts at a 100% energy. The only way I could think of it is a recursive function. Here's what I came up: E(t) = Et - .03*Et-1 E(0) = 1 E(1) = 1 - .03*E0 E(2) = E1 - .03*E1 .... Where E = Energy and t = each time turned on. I feel like the solution should be something close to E-.03t but it's not. I know the recursive function describes it exactly but I have to wonder if it's even possible to turn this into a differential equation? Thanks.