finite sum equation?

Question

How do you find an equation in terms of n that gives the sum of the first n integers squared. (1^2 + 2^2 + 3^2... + n^2)

Answer 1

n(n+1)(2n+1)/6

try it

1^2 + 2^2 + 3^3 ....6^2

6(6+1)(2x6+1)/6
= 7x13=91

Answer 2

Sum from i = 1 to n of i^2
You have to write this in sigma notation.

Answer 3

you go with n ? { n(n + one million) } 0 First multiply out : n ? { n² + n } = 0 ?n² + ?n = n (n + one million) (2n + one million) . . . . . . n (n + one million) ----------------------- . + . ---------------- . . . . . . 6 . . . . . . . . . . . . . . 2 and this simplifies to ? n (n - one million) (n + one million), or ? n (n² - one million) . . . . . . . . . . (and remember that n commences at 0)