Hi My Friends , What's up ?

The sum of squares :

1^2 + 2^2 + 3^2 + ... + n^2= n(n+1)(2n+1)/6

I have two questions :

1- how do we derived the equation above ??

2- what is the equation for the following sum :

(1^0.25)+(2^0.25)+(3^0.25)+ ... +(n^0.25)

Thank you very much