Question

What is the sum of the geometric sequence 8, –16, 32 … if there are 15 terms?

Answer 1

\[a\frac{(1-r^{n+1})}{(1-r)}\]

Answer 2

so would it be 87384?

Answer 3

\[\sum _{n=0}^{15} (8)(-2)^n\]

\[8\sum _{n=0}^{14} (-2)^n\]

8((1-(-2)^15))/(1+2)

http://www.wolframalpha.com/input/?i=8%28%281-%28-2%29%5E15%29%29%2F%281%2B2%29

yes

Answer 4

wanna do some more for me? :)

Answer 5

no, I think you can handle it

Answer 6

I don't think so

Answer 7

yes, you got the right answer

Answer 8

i googled it... i wanted to see if it was correct

Answer 9

do some more , you will get the hang of it

Answer 10

Thanks.

Answer 11

and if you get stuck , post it ; you will be helped