Hello, I hope I have posted this in the correct place, if not, sorry. Okay, I have just started working through the material, but I am having some problems working out one of the examples, which is given below: Un+2 = 12Un+1 - 20Un (n = 0,1,2...) We are given U0 = 1, U1 = 2 and are asked to work out U2 to U4. But, maybe my head is just blocked, but I can't seem to get the figures. I have looked at the answers at the back of the book, but still no luck. So, if anyone could point me in the right direction, I would be very thankful. Cheers Sean PS - Sorry about typing the question out, I haven't got the hang of LaTeX just yet.