First of all, i'm not sure if this topic belongs in this board. In either case...
I'm having a hard time following a particular generating function problem. I understand generating functions and I have the entire problem worked out infront of me, I am just clueless as to how they go from one step to the next.
An easy example problem is:
Find the general formula for an = F(n) using generating functions:
a_n+2 = 5a_n+1 ¡ 4a_n, a_0 = 1, a_1 = 2;
f(x) = the sum of a_nx^n from 0 to infinity.
The first step is
How is this step achieved? How are these two equal?