The fibonacci sequence, F(n) is defined:

F(n) = F(n-1) + F(n-2) for each n = 2,3,... with F(0)=1 and F(1)=1.

Use strong induction to prove that

F(n) = [PHI^(n+1)-(-PHI)^(-n-1)] / (sqrt(5)) for each integer n greater than or equal to 0.

Where PHI=(1+sqrt(5))/2

Please help!!