Question

Given the sequence 2, 8, 32, 128, 512 … , what is S10 ?

Answer 1

524,288

Answer 2

That's what i got but its not in the multiple choice answers.. :(
A. 174,762
B. 699,050
C. 2,796,202
D. 1,073,741,823

Answer 3

\(\sum_{n=1}^{10}2^{2n-1}=699050\)

Answer 4

Well i guess this guy is right.

Answer 5

So its B... Im still confused on how though to be honest.

Answer 6

do you get why I used \(2^{2n-1}\)?

Answer 7

Yeah.. i think.

Answer 8

well then, what is confusing? I just added them up

Answer 9

Okay now i get it. I guess I was confused on how you found that in the first place.... but i get it now. Thanks!

Answer 10

\(2^{2*1-1}+2^{2*2-1}+.....+2^{2*10-1}\)

Answer 11

np

Answer 12

you just have to see the pattern
we have
2 = 2^1
8=2^3
32=2^5
.....
so we needed something that would index 1,3,5.... and 2n-1 will do that.