need help on discrete structures

Prove the following by mathematical induction 1+4_94 2, 1 + 3 + 5 + +(-1)"n2 = (-1)nn(n+1) +(2n-1)=n2 1- 4. Let f, be the ith Fibonacci number. l.e.,= 1, f2-1, and fi-fi-1 + fi-2. Show that f1 + f2 + . . . + fn = fn+2-1. 5. Show that f, ) . gives That gives you an idea of how quickly the Fibonacci sequence grows! Be careful in the last two problems. Is the induction based on the Fibonacci rule, or is it based on the "add n terms" rules, like the first three problems