I was just working on proving the Fibonacci sequence and the Golden ratio i think, but i was having one problem. I was asked to prove that An=Bn, where An+2=An+1 + An (the fibonacci sequence) and that Bn=1/root5 [(1+root5/2)^n - (1 - root5/2)^n]. I understood the whole problem and was half way in completing until i wasn't able to go any further. Knowin that the limit existed i came up with L=[1+/- root 5 ]/2 then i was told that C+D=1 and C(L)+D(-L)=1, and by solving for C and D by these two equations, i would get Bn=1/root5 [(1+root5/2)^n - (1 - root5/2)^n]. But the values of C and D cancel out or i m getting like a zero for one of them. What did i do wrong, and what am i suppose to do next?