# Math Help - Induction Emergency!

1. ## Induction Emergency!

I have a test tomorrow and I'm really confused on induction. I was able to figure out one of my homework problems, but I'm having trouble with this one:

Directions - Use mathematical induction to prove the given formula for every positive integer n.

I could really use help! Thanks!

2. $\sum_{i=1}^{n+1} i(i+1) =$

$\left[ \sum_{i=1}^n i(i+1) \right] + (n+1)(n+2) =$

$\frac{n(n+1)(n+2)}{3} + (n+1)(n+2) =$

$\frac{n(n+1)(n+2)}{3} + \frac{3(n+1)(n+2)}{3} =$

$\frac{n(n+1)(n+2) + 3(n+1)(n+2)}{3} =$

$\frac{(n+1)(n+2)(n + 3)}{3} = \sum_{i=1}^{n+1} i(i+1)$