Hi, could someone please explain how to do this:

use induction to prove that

$\displaystyle

\sum_{i=1}^n i^2 = \frac{n(n+1)(2n+1)}{6}

$

for all positive integer n.

[Note: $\displaystyle \sum_{i=1}^n i^2$ means the sum $\displaystyle 1^2+2^2+3^2+...+n^2$]

thank you!!!