## anonymous 5 years ago sigma (E) with 3 on top. n=0 on bottom. what does this mean??

1. anonymous

on the side on sigma, it is sin$\pi$ over 4

2. anonymous

$\sum_{n=0}^{3}\sin \pi/4$ ?

3. anonymous

Look something like that?

4. anonymous

theres an n before the pi symbol, but other than that its right

5. anonymous

$Ok so \sum_{n=0}^{3}\sin (n*\pi/4)$ So like this?

6. anonymous

Well without the okso at the beginning.

7. anonymous

yeah thats right

8. anonymous

The sigma represents a summation. So if it were $\sum_{n=0}^{3}n$ we start with n=0 plug that value in and keep adding until we reach the limit which is the top value on the sigma, 3.

9. anonymous

So we'd have 0+1+2+3 and then stop.

10. anonymous

so when n=0, the whole thing would equal 0 right?

11. anonymous

Yes. You start with whatever n equals under the sigma and plug it into the function to the left of the sigma and then go to the next sequential n value and add it to that result.

12. anonymous

so do i just start with n=0 and I get 0, then n=1 I plug it into n*pi over 4 and that equals .785 and so I add that to the zero.... then i go on to n=2 and keep adding on to the .785......

13. anonymous

exactly!

14. anonymous

great thanks!

15. anonymous

good method...

16. anonymous

Do u still have doubts @linda ?