I am told that If n = 25, we have Sn = 121392 where Sn is the number of additions performed in the following function to calculate the nth fibonacci number.Can anyone explain how? Int F (int n) {if (n == 0) return (0); if (n == 1) return (1); return (F(n-1) +F(n-2));} How can I find and prove a formula for [math]f(n+1)^3 + f(n)^3 - f(n-1)^3[/math] for [math]n \geq 2[/math] where [math]f(n)[/math] is the nth Fibonacci number?