Question

Please help :)
Given the arithmetic sequence 23, 17, 11 …Evaluate this sigma notation!

Answer 1

Do you still need help?

Answer 2

yes! :/

Answer 3

23-7n

Answer 4

For n should is tart with1 al the way to 9? or start with 4 to 9?

Answer 5

Are you evaluating this to 0?

Answer 6

so from 4 to 9?

Answer 7

ok, one sec let me set this up.

Answer 8

okay

Answer 9

no instead of 30-7n its a(n)

Answer 10

What do you get? I think I get something like -81

Answer 11

thats not what my problem looks like :/ how did you get the 30-7n???

Answer 12

Okay, so what is the first term?

Answer 13

23 :)

Answer 14

23 would be the first term, so what about do you add to it to get 17

23+c=17

Answer 15

Right

Answer 16

yes the difference. so the equation would be 23+(n-1)6

Answer 17

Oh, sorry about the work earlier. I see that it's 6 and not 7. Ok...

So 6 would be the common difference.

Answer 18

29-6n right? :)

Answer 19

yes

Answer 20

Now what? :/

Answer 21

That would give you your first term, so it's correct.

Answer 22

so should i start with 29-6(4) all; the way to 9?

Answer 23

What would you get if you add the terms from 4 to 9?

Answer 24

No,

Answer 25

Actually, you are correct. I Thought you mean only 4 and 9.

Answer 26

*meant

Answer 27

no all the way through (4,5,6,7,8,9) lol

Answer 28

That's correct.

Answer 29

Let me know what you get.

Answer 30

kay hold onnn

Answer 31

-60?

Answer 32

yep. Good Job!

Answer 33

Thanks!

Answer 34

Yep!