Question

Evaluate the series:
Enter only a numerical answer.

Answer 1

hold up im getting the problem

Answer 2

\[\sum_{k=1}^{20}k^{2}\]

Answer 3

@terenzreignz do u know it?

Answer 4

Well, we have a formula for this sort of thing...
\[\huge \sum_{k=1}^n k^2 = \frac{n(n+1)(2n+1)}{6}\]

Plug in, and you're good to go :)

Answer 5

i got it wrong

Answer 6

:(

Answer 7

That's a pity... what answer did you enter?

Answer 8

2087

Answer 9

How?

Answer 10

i entered 20 for n

Answer 11

Okay... with you so far...
\[\huge \frac{\color{red}{20}(\color{red}{20}+1)[2(\color{red}{20})+1]}{6}\]

Answer 12

Simplifying would yield...
\[\huge \frac{\color{red}{20}\times\color{green}{21}\times\color{blue}{41}}{6}\]

Answer 13

yes

Answer 14

Well, that's strange, I get a different answer, not 2087

Answer 15

lol

Answer 16

Either your calculator is busted... (hopefully not) or you have fallen victim to human error... we all do...

Answer 17

2870

Answer 18

There. Right and proper :)

Answer 19

lol

Answer 20

I'm still wondering how you ended up with 2087...

Answer 21

lol still wrong though

Answer 22

You'll get another chance :)

Best of luck :D

Answer 23

wat?

Answer 24

Never mind. Just avoid carelessness next time :)

Answer 25

how careless i still have a chance to get it right

Answer 26

Then grab that chance and redeem yourself :)

Answer 27

how idk how to do the problem thats why im on here

Answer 28

I just told you how to do that (specific) problem?

Answer 29

no u didnt and u had the same answer as me

Answer 30

I got 2870...

Answer 31

ya and your wrong

Answer 32

Google says otherwise
https://www.google.co.uk/search?q=20*21&aq=f&oq=20*21&aqs=chrome.0.57.1709j0&sourceid=chrome&ie=UTF-8#hl=fil&sclient=psy-ab&q=1%2B4%2B9%2B16%2B25%2B36%2B49%2B64%2B81%2B100%2B121%2B144%2B169%2B196%2B225%2B256%2B289%2B324%2B361%2B400&oq=1%2B4%2B9%2B16%2B25%2B36%2B49%2B64%2B81%2B100%2B121%2B144%2B169%2B196%2B225%2B256%2B289%2B324%2B361%2B400&gs_l=serp.3...9831.12755.2.12934.7.7.0.0.0.0.122.774.0j7.7.0...0.0...1c.1.12.psy-ab.9-23oNuz6Fg&pbx=1&fp=1&biw=1366&bih=667&bav=on.2,or.r_qf.&cad=b&sei=WkiLUbOVK8ftrAf36oDgCA

Answer 33

So, I assure you,
\[\LARGE \sum_{k=1}^{20}k^2 =2870\]

But then again, there's the chance you entered your question incorrectly.

Answer 34

no its exactly how it looks

Answer 35

@UnkleRhaukus can u confirm this

Answer 36

@ajprincess can u confirm this

Answer 37

I had google confirm it, by typing out the sum... manually
1+4+9+16.... etc up to 400

Answer 38

yup i too am getting 2870:)

Answer 39

thanks

Answer 40

welcome:)

Answer 41

\[\sum\limits_{k=1}^{20}k^2=2870\checkmark\]