## anonymous one year ago Expeess the series 1+4+9+16 using sigma notation

1. Empty

Ahhh this is a fun one! Any ideas? Give it your best shot and guess and I'll help you understand. I remember when I first saw sigma notation I didn't understand it either, but through guessing I can understand where you need help in understanding.

2. skullpatrol

want a hint?

3. anonymous

Yes

4. Empty

Not even gonna try? :(

5. skullpatrol

$$\Huge1^2 = 1$$$$\Huge2^2 = 4$$$$\Huge3^2 = 9$$$$\Huge4^2 =16$$

6. anonymous

Do i add 1+4+9+16 by any chance? Sorry i dont remember how to do this

7. skullpatrol

yes

8. skullpatrol

Sigma notation is a shorthand way of writing: n + (n+1) + (n+2) + ...

9. skullpatrol

$\sum_{1}^{4}$

10. skullpatrol

"Sigma" means "sum"

11. anonymous

Oh ok.

12. skullpatrol

|dw:1436362346004:dw|

13. anonymous

1+4+9+16 =30 So n^2 has to equal 30 too?

14. skullpatrol

30 is what the sum equals.

15. skullpatrol

|dw:1436362667428:dw|

16. skullpatrol

|dw:1436362706460:dw|

17. skullpatrol

recall: 4! = 1*2*3*4 = 24

18. skullpatrol

that^ is called factorial notation

19. skullpatrol

sigma notation uses pluses

20. anonymous

Ok

21. anonymous

So is the answer is n^2=30?

22. skullpatrol

|dw:1436441192523:dw|