Hi, It can be derived as follows... Let f(n) denote the no. of ways in which 'n' steps can be climbed... So, for climbing 'n' steps, the possible combinations are,
1. Climb one step initially.. so, n-1 steps left.. they can be climbed in f(n-1) ways, OR 2. Climb 2 steps initally... so, n-2 steps left.. that can be climbed in f(n-2) ways. So, f(n)=f(n-1)+f(n-2), which is nothing but fibonacci series.. with f(0)=1 and f(1)=1 (Obviously..) for climbing 0 and 1 steps... Vikram
