Question

help please!

Evaluate the series:

Enter only a numerical answer.
I'm not sure if you would add up 1^2...20^2 on this one?

Answer 1

\[\sum_{k=1}^{20} k\]

Answer 2

\[\sum_{k=1}^{20}k ^{2}=1^{2}+2^{2}+3^{2}+...+20^{2}\]
\[\sum n ^{2}=\frac{ n \left( n+1 \right)\left( 2n+1 \right) }{6 }\]
put n=20 and get the solution.

Answer 3

2870?

Answer 4

yes you are correct.